Add Godot 4.x camera module support with display rotation and CameraFeed formats

[shiena]

split from https://github.com/godotengine/godot/pull/106305 and merge from https://github.com/godotengine/godot/pull/106777

This PR adds comprehensive Godot 4.x support for the iOS camera module with the following improvements:

• File separation for version-specific code: Split camera implementation into camera_ios.mm (Godot 3.x) and camera_ios_4x.mm (Godot 4.x) to reduce #if directive complexity
• Display rotation handling: Added handle_display_rotation_change() support for Godot 4.6+ to properly handle camera feed orientation when device rotates
• CameraFeed format support: Implemented get_formats() and set_format() for Godot 4.5+ allowing users to query and select camera formats
• Lazy feed initialization: For Godot 4.5+, camera feeds are now initialized via set_monitoring_feeds() instead of constructor, following the new CameraServer pattern

Version Compatibility

• Godot 3.x: Uses camera_ios.mm (unchanged behavior)
• Godot 4.0-4.4: Basic camera functionality
• Godot 4.5+: CameraFeed format selection support
• Godot 4.6+: Display rotation change callback support

[shiena]

This pull request contains changes for the upcoming 4.6 release, so I'll mark it as ready for review once 4.6 is released.