[FLINK-30093][protobuf] Fix compile errors for google.protobuf.Timestamp type

[baugarten]

What is the purpose of the change

This PR backports this PR, which fixes some compilation errors in the flink-protobuf package.

Brief change log

Cherry-picks the PR against the release-1.16 branch. The commit applied cleanly.

Verifying this change

The cherry-picked commit introduces a new test cases, which should succeed.

Does this pull request potentially affect one of the following parts:

• Dependencies (does it add or upgrade a dependency): no
• The public API, i.e., is any changed class annotated with @Public(Evolving): no
• The serializers: no
• The runtime per-record code paths (performance sensitive): no
• Anything that affects deployment or recovery: JobManager (and its components), Checkpointing, Kubernetes/Yarn, ZooKeeper: no
• The S3 file system connector: no

Documentation

• Does this pull request introduce a new feature? no
• If yes, how is the feature documented? not applicable

[flinkbot]

CI report:

• 9e30572 Azure: SUCCESS

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