gcs-data-bucket metadata key is now modifiable by the user (#12505)

Author: bcreddy-gcp

mmv1/templates/terraform/constants/workbench_instance.go.tmpl

@@ -42,7 +42,6 @@ var WorkbenchInstanceProvidedMetadata = []string{
     "dataproc-service-account",
     "disable-check-xsrf",
     "framework",
-    "gcs-data-bucket",
     "generate-diagnostics-bucket",
     "generate-diagnostics-file",
     "generate-diagnostics-options",