REGRESSION (276971@main): [visionOS] Some websites cannot be scrolled

https://bugs.webkit.org/show_bug.cgi?id=272467
rdar://126142996

Reviewed by Tim Horton.

The _spatialTrackingView is interefering with scrolling layers in the WKContentView's view
hierarchy. Both make the view centered and 0w x 0h, as well as disabling the spatial tracking
view's user interaction flag.

* Source/WebKit/UIProcess/ios/WKContentView.mm:
(-[WKContentView _commonInitializationWithProcessPool:configuration:]):

Canonical link: https://commits.webkit.org/277342@main

Source/WebKit/UIProcess/ios/WKContentView.mm

@@ -274,8 +274,9 @@ - (instancetype)_commonInitializationWithProcessPool:(WebKit::WebProcessPool&)pr
     [_spatialTrackingView layer].separatedState = kCALayerSeparatedStateTracked;
     _spatialTrackingLabel = makeString("WKContentView Label: "_s, createVersion4UUIDString());
     [[_spatialTrackingView layer] setValue:(NSString *)_spatialTrackingLabel forKeyPath:@"separatedOptions.STSLabel"];
-    [_spatialTrackingView setAutoresizingMask:UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight];
-    [_spatialTrackingView setFrame:self.bounds];
+    [_spatialTrackingView setAutoresizingMask:UIViewAutoresizingFlexibleLeftMargin | UIViewAutoresizingFlexibleRightMargin | UIViewAutoresizingFlexibleTopMargin | UIViewAutoresizingFlexibleBottomMargin];
+    [_spatialTrackingView setFrame:CGRectMake(CGRectGetMidX(self.bounds), CGRectGetMidY(self.bounds), 0, 0)];
+    [_spatialTrackingView setUserInteractionEnabled:NO];
     [self addSubview:_spatialTrackingView.get()];
 #endif