chore(iam-policy): remove proto path that is not copied from generation config (#13025)

These proto path are configured in generation_config.yaml, but not
copied in
[.OwlBot-hermetic.yaml](https://github.com/googleapis/google-cloud-java/blob/main/java-iam-policy/.OwlBot-hermetic.yaml).
Expect that this change should not lead to code changes after generate
workflow runs.

For #13024
For googleapis/librarian#5730

---------

Co-authored-by: cloud-java-bot <cloud-java-bot@google.com>

Author: zhumin8

generation_config.yaml

@@ -1335,8 +1335,6 @@ libraries:
   excluded_poms: proto-google-iam-v1-bom,google-iam-policy,proto-google-iam-v1
   excluded_dependencies: google-iam-policy
   GAPICs:
-  - proto_path: google/iam/v1
-  - proto_path: google/iam/v1beta
   - proto_path: google/iam/v2
   - proto_path: google/iam/v2beta
   - proto_path: google/iam/v3