Update EntrustPermissionTrait.php

[itashia]

Summary of Improvements

• Added precise return types for roles() and boot method
• Renamed boot() to bootEntrustPermissionTrait() to prevent trait conflicts
• Replaced sync([]) with detach() for better clarity and intent
• Removed redundant return true from model event listener
• Cleaned up formatting and long lines
• Explicitly imported BelongsToMany for better readability

All changes are non-breaking and maintain the original behavior.