[java-managed-identities] both v1 and v1beta in config but only v1 code present

[zhumin8]

Both versions configured in generation_config.yaml, but only v1 is present in code.

google-cloud-java/generation_config.yaml

Lines 1541 to 1543 in 55c9857

	GAPICs:
	- proto_path: google/cloud/managedidentities/v1
	- proto_path: google/cloud/managedidentities/v1beta1

https://github.com/googleapis/google-cloud-java/tree/main/java-managed-identities

[zhumin8]

java-os-login also have same issue.