[autostart] Allow Configurable Bundle Identifier for LaunchAgent (macOS)

Currently, `tauri-plugin-autostart` does not set an associated bundle identifier when creating the LaunchAgent plist on macOS. This can result in issues such as macOS not displaying the correct app name in the Startup Items settings. It would be better to add a configuration option to allow developers to specify a custom associated bundle identifier for the LaunchAgent plist on macOS.

# References
- [Updating helper executables from earlier versions of macOS](https://developer.apple.com/documentation/servicemanagement/updating-helper-executables-from-earlier-versions-of-macos#Connect-services-to-app-names-in-System-Settings)