chore: update librarian version to v0.46.0

[JoeWang1127]

Update librarian version to v0.46.0.

Debug Info

System Details

• JDK version: javac 21.0.12.1
• Maven version: Apache Maven 3.9.9 (8e8579a9e76f7d015ee5ec7bfcdc97d260186937)
• OS: Linux 7.1.6-1rodete1-amd64 x86_64
• Librarian version: v0.46.0

Commands Executed

• go run github.com/googleapis/librarian/cmd/librarian@latest update version
• go run github.com/googleapis/librarian/cmd/librarian@v0.46.0 tidy
• go run github.com/googleapis/librarian/cmd/librarian@v0.46.0 install
• go run github.com/googleapis/librarian/cmd/librarian@v0.46.0 generate --all
• git add .
• git commit -m "chore: update librarian version to v0.46.0"

Included Librarian Updates

• feat(internal/librarian/java): tidy redundant issue_tracker_override matching sdk.yaml librarian#7652: feat(internal/librarian/java): tidy redundant issue_tracker_override matching sdk.yaml
• chore(main): release 0.46.0 librarian#7653: chore(main): release 0.46.0
• fix(generate): race related to docindex librarian#7691: fix(generate): race related to docindex
• fix(internal/sidekick): restore protocol method librarian#7689: fix(internal/sidekick): restore protocol method

[gemini-code-assist]

Code Review

This pull request removes the "issue_tracker" field from the ".repo-metadata.json" configuration files across various Java Google Cloud client libraries. I have no feedback to provide as there are no review comments.