ci: disable add-and-commit fetch in build-protocol

The default 'git fetch --tags --force' pulls 100+ refs at once and the
action aborts before committing the generated stubs. This step doesn't
pull or tag, so the fetch is unused here.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: chenghao-mou

.github/workflows/build-protocol.yml

@@ -55,6 +55,10 @@ jobs:
           add: '["livekit-protocol/"]'
           default_author: github_actions
           message: generated protobuf
+          # Skip the default `git fetch --tags --force`: on this repo it pulls
+          # 100+ refs at once and the action aborts before committing. Committing
+          # generated stubs onto the PR head branch doesn't need a full fetch.
+          fetch: false
 
   build_wheels:
     name: Build Protocol wheel/sdist