dataform: promote google_dataform_repository to GA

[modular-magician]

Promotes the Dataform Repository resource (google_dataform_repository), its associated IAM resources (google_dataform_repository_iam_*), and all properties from Beta to GA.

Changes

• Repository.yaml:
  • Removed min_version: beta from the top-level resource, IAM policy config, samples, and all fields/parameters.
  • Updated API and tokenStatus reference URLs from v1beta1 to v1.
• Terraform Sample Templates: Removed provider = google-beta from all sample .tf.tmpl files so valid GA documentation and test configurations are generated.
• Handwritten VCR Tests: Removed Beta version guards ({{- if ne $.TargetVersionName "ga" }}), updated provider factories to ProtoV5ProviderFactories, and removed provider = google-beta in resource_dataform_repository_test.go.tmpl.

Verification & Testing

1. Provider Generation: Generated clean provider code across all services for both GA and Beta.
2. Binary Build: Executed make build (go install, go vet, and gofmtcheck) in both terraform-provider-google (GA) and terraform-provider-google-beta (Beta). Both built cleanly without errors.
3. Test Package Compilation: Executed go test -c ./google/services/dataform in GA and go test -c ./google-beta/services/dataform in Beta. All test suites and sample configurations compiled successfully.

`google_dataform_repository`

`google_dataform_repository_iam_policy`

`google_dataform_repository_iam_binding`

`google_dataform_repository_iam_member`

Derived from GoogleCloudPlatform/magic-modules#18398