Update Bicep form with pre-deployment input validation

[glennmusa]

Description

Deploying using the marketplace UI template fails with this error:

{
    "status": "Failed",
    "error": {
        "code": "InvalidResourceLocation",
        "message": "The specified location '[parameters('sharedServicesLocation')]' is invalid. A location must consist of characters, whitespace, digit, or following symbols '(,)'."
    }
}

Steps to Reproduce

Try to deploy from the Marketplace UI at src/bicep/ui/ like so:

Steps to reproduce the behavior:

1. Click the Deploy to Azure button
2. Receive an error about shared services location

Expected behavior

Deployment succeeds without modifying any input

Actual behavior

Deployment fails on InvalidResourceLocation

Screenshots

Additional context

n/a

[brooke-hamilton]

Add a checkbox to the PR template that asks if the UI template has been updated when a parameter is added or changed.