ci: update workflows and extend detect-secrets exclude (#10286)

* chore: update pre-commit configuration to exclude specific JSON file from secrets detection

- Modified the exclude pattern for the detect-secrets hook to prevent false positives for the component_index.json file located in src/lfx/src/lfx/_assets.

* ci: update GitHub Actions workflow to enhance security for pull request handling

- Changed the event trigger from `pull_request` to `pull_request_target` to improve security when handling forked pull requests.
- Updated conditions for repository checkout and dependency installation to ensure safe execution only for same-repo pull requests.
- Adjusted PR comment conditions to reflect the new event trigger, maintaining functionality for both community forks and same-repo updates.