chore: Enable requesting numeric enums in "transport=rest" responses …

…for services supporting this (#40)

* chore: Enable requesting numeric enums in "transport=rest" responses for services supporting this (Java, Go, Python, PHP, TypeScript, C#, and Ruby), even if they do not yet turn on REST transport

chore: disallow "transport=rest" for services where numeric enums are not confirmed to be supported (except in PHP and Java)
PiperOrigin-RevId: 493113566

Source-Link: googleapis/googleapis@758f0d1

Source-Link: googleapis/googleapis-gen@78bd8f0
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packages/google-cloud-gke-backup/google/cloud/gke_backup_v1/services/backup_for_gke/client.py

@@ -547,9 +547,6 @@ def __init__(
             transport (Union[str, BackupForGKETransport]): The
                 transport to use. If set to None, a transport is chosen
                 automatically.
-                NOTE: "rest" transport functionality is currently in a
-                beta state (preview). We welcome your feedback via an
-                issue in this library's source repository.
             client_options (Optional[Union[google.api_core.client_options.ClientOptions, dict]]): Custom options for the
                 client. It won't take effect if a ``transport`` instance is provided.
                 (1) The ``api_endpoint`` property can be used to override the