This function is required by the Steinberg VST3 validator from VST 3.7
onwards.

This prevents test failures in the Steinberg VST3 validator.

When rendering with OpenGL, the paint function is called from a
background thread. If we call `isMouseOver` from the paint function, we
may end up calling native functions via the ComponentPeer, which causes
threading warnings on macOS.

This commit also removes the subview from its superview's subview array before re-ordering as the macOS docs don't make any guarantees about what happens when adding a subview that is already contained in the array.

This prevents components from taking focus when they are blocked by another modal component by excluding them from the list of child handlers returned by AccessibilityHandler::getChildren() and fixes an issue with modal components being dismissed by handlers.