feat: Add forecasted e2e test (Azure#3059)

## Description

Closes Azure#2423

## Pipeline Reference

<!-- Insert your Pipeline Status Badge below -->

| Pipeline |
| -------- |
|
[![avm.res.consumption.budget](https://github.com/Azure/bicep-registry-modules/actions/workflows/avm.res.consumption.budget.yml/badge.svg?branch=users%2Fsegraef%2F2442)](https://github.com/Azure/bicep-registry-modules/actions/workflows/avm.res.consumption.budget.yml)
|

## Type of Change

<!-- Use the checkboxes [x] on the options that are relevant. -->

- [ ] Update to CI Environment or utilities (Non-module affecting
changes)
- [x] Azure Verified Module updates:
- [ ] Bugfix containing backwards-compatible bug fixes, and I have NOT
bumped the MAJOR or MINOR version in `version.json`:
- [ ] Someone has opened a bug report issue, and I have included "Closes
#{bug_report_issue_number}" in the PR description.
- [ ] The bug was found by the module author, and no one has opened an
issue to report it yet.
- [ ] Feature update backwards compatible feature updates, and I have
bumped the MINOR version in `version.json`.
- [ ] Breaking changes and I have bumped the MAJOR version in
`version.json`.
  - [x] Update to documentation

## Checklist

- [x] I'm sure there are no other open Pull Requests for the same
update/change
- [x] I have run `Set-AVMModule` locally to generate the supporting
module files.
- [x] My corresponding pipelines / checks run clean and green without
any errors or warnings

<!-- Please keep up to date with the contribution guide at
https://aka.ms/avm/contribute/bicep -->

avm/res/consumption/budget/README.md

@@ -26,8 +26,9 @@ The following section provides usage examples for the module, which were used to
 >**Note**: To reference the module, please use the following syntax `br/public:avm/res/consumption/budget:<version>`.
 
 - [Using only defaults](#example-1-using-only-defaults)
-- [Using large parameter set](#example-2-using-large-parameter-set)
-- [WAF-aligned](#example-3-waf-aligned)
+- [Using `thresholdType` `Forecasted`](#example-2-using-thresholdtype-forecasted)
+- [Using large parameter set](#example-3-using-large-parameter-set)
+- [WAF-aligned](#example-4-waf-aligned)
 
 ### Example 1: _Using only defaults_
 
@@ -89,7 +90,71 @@ module budget 'br/public:avm/res/consumption/budget:<version>' = {
 </details>
 <p>
 
-### Example 2: _Using large parameter set_
+### Example 2: _Using `thresholdType` `Forecasted`_
+
+This instance deploys the module with the minimum set of required parameters and `thresholdType` `Forecasted`.
+
+
+<details>
+
+<summary>via Bicep module</summary>
+
+```bicep
+module budget 'br/public:avm/res/consumption/budget:<version>' = {
+  name: 'budgetDeployment'
+  params: {
+    // Required parameters
+    amount: 500
+    name: 'cbfcst001'
+    // Non-required parameters
+    contactEmails: [
+      '[email protected]'
+    ]
+    location: '<location>'
+    thresholdType: 'Forecasted'
+  }
+}
+```
+
+</details>
+<p>
+
+<details>
+
+<summary>via JSON Parameter file</summary>
+
+```json
+{
+  "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentParameters.json#",
+  "contentVersion": "1.0.0.0",
+  "parameters": {
+    // Required parameters
+    "amount": {
+      "value": 500
+    },
+    "name": {
+      "value": "cbfcst001"
+    },
+    // Non-required parameters
+    "contactEmails": {
+      "value": [
+        "[email protected]"
+      ]
+    },
+    "location": {
+      "value": "<location>"
+    },
+    "thresholdType": {
+      "value": "Forecasted"
+    }
+  }
+}
+```
+
+</details>
+<p>
+
+### Example 3: _Using large parameter set_
 
 This instance deploys the module with most of its features enabled.
 
@@ -175,7 +240,7 @@ module budget 'br/public:avm/res/consumption/budget:<version>' = {
 </details>
 <p>
 
-### Example 3: _WAF-aligned_
+### Example 4: _WAF-aligned_
 
 This instance deploys the module in alignment with the best-practices of the Azure Well-Architected Framework.
 

avm/res/consumption/budget/main.json

@@ -5,8 +5,8 @@
   "metadata": {
     "_generator": {
       "name": "bicep",
-      "version": "0.28.1.47646",
-      "templateHash": "13231547958069431465"
+      "version": "0.29.47.4906",
+      "templateHash": "9899827298268482806"
     },
     "name": "Consumption Budgets",
     "description": "This module deploys a Consumption Budget for Subscriptions.",

avm/res/consumption/budget/tests/e2e/forecasted/main.test.bicep

@@ -0,0 +1,37 @@
+targetScope = 'subscription'
+
+metadata name = 'Using `thresholdType` `Forecasted`'
+metadata description = 'This instance deploys the module with the minimum set of required parameters and `thresholdType` `Forecasted`.'
+
+// ========== //
+// Parameters //
+// ========== //
+
+@description('Optional. The location to deploy resources to.')
+param resourceLocation string = deployment().location
+
+@description('Optional. A short identifier for the kind of deployment. Should be kept short to not run into resource-name length-constraints.')
+param serviceShort string = 'cbfcst'
+
+@description('Optional. A token to inject into the name of each resource.')
+param namePrefix string = '#_namePrefix_#'
+
+// ============== //
+// Test Execution //
+// ============== //
+
+@batchSize(1)
+module testDeployment '../../../main.bicep' = [
+  for iteration in ['init', 'idem']: {
+    name: '${uniqueString(deployment().name)}-test-${serviceShort}-${iteration}'
+    params: {
+      name: '${namePrefix}${serviceShort}001'
+      location: resourceLocation
+      amount: 500
+      contactEmails: [
+        '[email protected]'
+      ]
+      thresholdType: 'Forecasted'
+    }
+  }
+]