Fixes for Alloydb E2E tests

[wiktorn]

Failures

• too long project name in Sipmle example resulted in:

Error: "***-alloydb-prj" name must be 4 to 30 characters with lowercase and uppercase letters, numbers, hyphen, single-quote, double-quote, space, and exclamation point.

• using self_link resulted in:

Error: Error creating Cluster: googleapi: Error 499: malformed network path: "https://www.googleapis.com/compute/v1/projects/***/global/networks/e2e-test"

• Cross region replication stil fails with:

│ Error: Error creating cluster. Can not create secondary cluster without secondary_config field.
│
│   with module.alloydb.google_alloydb_cluster.secondary[0],
│   on /usr/local/google/home/wiktorn/git/cloud-foundation-fabric/modules/alloydb/main.tf line 199, in resource "google_alloydb_cluster" "secondary":
│  199: resource "google_alloydb_cluster" "secondary" {

• Custom flags and users definition:

Error: Error creating User: googleapi: Error 400: Invalid resource state for "projects/364296783266/locations/europe-west4/clusters/primary": primary instance is not found  

• Non empty plan after apply (for Simple example)

  # module.alloydb.google_alloydb_cluster.primary will be updated in-place
  ~ resource "google_alloydb_cluster" "primary" {
      + display_name           = "db"
        id                     = "projects/***/locations/europe-west4/clusters/db"
        name                   = "projects/***/locations/europe-west4/clusters/db"
        # (20 unchanged attributes hidden)

        # (3 unchanged blocks hidden)
    }

  # module.alloydb.google_alloydb_instance.primary will be updated in-place
  ~ resource "google_alloydb_instance" "primary" {
        id                    = "projects/***/locations/europe-west4/clusters/db/instances/db"
        name                  = "projects/***/locations/europe-west4/clusters/db/instances/db"
        # (19 unchanged attributes hidden)

      + network_config {
          + enable_public_ip = false
        }

        # (3 unchanged blocks hidden)
    }

Plan: 0 to add, 2 to change, 0 to destroy.

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Checklist

I applicable, I acknowledge that I have:

• Read the contributing guide
• Ran terraform fmt on all modified files
• Regenerated the relevant README.md files using tools/tfdoc.py
• Made sure all relevant tests pass