Merge pull request #105225 from bruvzg/ds_gdsoft

Change `DisplayServerMacOS` from `GDCLASS` to `GDSOFTCLASS`. Add `GDSOFTCLASS` to other display servers.

tests/display_server_mock.h

@@ -37,6 +37,8 @@
 // Specialized DisplayServer for unittests based on DisplayServerHeadless, that
 // additionally supports things like mouse enter/exit events and clipboard.
 class DisplayServerMock : public DisplayServerHeadless {
+	GDSOFTCLASS(DisplayServerMock, DisplayServerHeadless);
+
 private:
 	friend class DisplayServer;