[sdk-platform-java] generated modules are not in monorepo config after merge

[zhumin8]

showcase, common-protos and iam from https://github.com/googleapis/sdk-platform-java/blob/main/generation_config.yaml are not in google-cloud-java/generation-config.yaml

[chingor13]

Need to figure out how to move the protos into a non-root folder

[suztomo]

Need to figure out how to move the protos into a non-root folder

Joe @JoeWang1127 also wants to relocate the modules from sdk-platform-java to the root (googleapis/librarian#5326).

[chingor13]

Waiting for the current generation PR to regenerate everything. We expect to see some new classes in java-iam

[chingor13]

The generation PR is generating IAM correctly now: 0a5fe8e