fix: remove dangling agent symlinks that break checkout (redis#3334)

`.gemini/agents` and `.claude/agents` were committed in redis#3316 pointing at
`../.agents/agents`, a directory that was never created. GitHub Actions
staging refuses dangling symlinks, so any job that checks out
`redis/node-redis@master` (e.g. the redis-oss release-automation test job)
fails during "Set up job" before any test runs.

Remove both broken symlinks. The valid `.claude/skills` -> `../.agents/skills`
link is kept.

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

Author: nkaradzhov