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

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.

The previously used getUserDefaultUILanguage() was based on the deprecated
LCID/LANGID concept. It had an increasing number of corner cases as not
every locale had associated LCIDs. The new solution is based on locale
names (string based) and will return reasonable names in more situations.

When bridging 32-bit/64-bit plugins on Windows, the plugin is hosted in
an auxilliary process, and the plugin's editor is embedded into an HWND
owned by a different process (the plugin host).

Previously, the `isForegroundProcess` check would fail for bridged
plugins, because the foreground window may belong to the DAW, rather
than to the auxilliary hosting process.

This patch adds an additional check, to find whether the same process
owns both the foreground window, and the window which embeds the
PopupMenu's target component. In this case, we avoid immediately
dismissing the PopupMenu.