Add CameraFeed support for iOS

[shiena]

Split iOS definitions (squashing #98416).
I tested on iPhone 15 Pro (iOS 18.4.1)

Relations:

• [macOS] Fix missing frame_changed signal to CameraFeed #104809
• macOS: Allow users to select Continuity Camera #104857
• Support CameraFeed format on macOS #106777

[shiena]

CI errors should be resolved in #104857 .

[shiena]

applied the diff

Diff to apply after merging #104857 .

diff --git a/modules/camera/camera_macos.mm b/modules/camera/camera_macos.mm
--- a/modules/camera/camera_macos.mm	(revision e37d785a0a7f41d37aa42fe3689e86f322c13dc3)
+++ b/modules/camera/camera_macos.mm	(date 1747067891596)
@@ -314,10 +314,14 @@
 	if (@available(macOS 10.15, *)) {
 #endif
 		AVCaptureDeviceDiscoverySession *session;
-		if (@available(macOS 14.0, *)) {
+		if (@available(macOS 14.0, iOS 17.0, *)) {
 			session = [AVCaptureDeviceDiscoverySession discoverySessionWithDeviceTypes:[NSArray arrayWithObjects:AVCaptureDeviceTypeExternal, AVCaptureDeviceTypeBuiltInWideAngleCamera, AVCaptureDeviceTypeContinuityCamera, nil] mediaType:AVMediaTypeVideo position:AVCaptureDevicePositionUnspecified];
 		} else {
-			session = [AVCaptureDeviceDiscoverySession discoverySessionWithDeviceTypes:[NSArray arrayWithObjects:AVCaptureDeviceTypeExternalUnknown, AVCaptureDeviceTypeBuiltInWideAngleCamera, nil] mediaType:AVMediaTypeVideo position:AVCaptureDevicePositionUnspecified];
+#if TARGET_OS_IPHONE || TARGET_OS_MACCATALYST
+            session = [AVCaptureDeviceDiscoverySession discoverySessionWithDeviceTypes:[NSArray arrayWithObjects:AVCaptureDeviceTypeBuiltInWideAngleCamera, nil] mediaType:AVMediaTypeVideo position:AVCaptureDevicePositionUnspecified];
+#else
+            session = [AVCaptureDeviceDiscoverySession discoverySessionWithDeviceTypes:[NSArray arrayWithObjects:AVCaptureDeviceTypeExternalUnknown, AVCaptureDeviceTypeBuiltInWideAngleCamera, nil] mediaType:AVMediaTypeVideo position:AVCaptureDevicePositionUnspecified];
+#endif
 		}
 		devices = session.devices;
 #if defined(__x86_64__)

[fire]

On a brief review I didn't see anything bad, but also probably want to test to see it works.

[shiena]

@fire A camera feed demo project is available.
godotengine/godot-demo-projects#1225