Add triage permissions for @Titan-Realtek

### Full Name

Titan Chen

### GitHub Username

@Titan-Realtek

### Organization

Realtek

### Supporting Documents

@Titan-Realtek has contributed the following [PRs](https://github.com/zephyrproject-rtos/zephyr/issues?q=state%3Aclosed%20label%3A%22platform%3A%20Realtek%20EC%22%20author%3ATitan-Realtek)