macOS: Apply light appearance to NSViewComponentPeer on 10.14 to fix a bug when hosting Apple AUs

modules/juce_gui_basics/native/juce_mac_NSViewComponentPeer.mm

@@ -122,6 +122,8 @@ public:
            #if defined (MAC_OS_X_VERSION_10_14)
             if (! [window isOpaque])
                 [window setBackgroundColor: [NSColor clearColor]];
+
+            [view setAppearance: [NSAppearance appearanceNamed: NSAppearanceNameAqua]];
            #endif
 
             [window setHasShadow: ((windowStyleFlags & windowHasDropShadow) != 0)];