TETRAEDGE: Do not show GUI confirmation dialog

Syberia has its own confirmation dialog. Syberia 2 does not seem
to ask for confirmation, but using the GUI confirmation does not
work anyway as if the user decides not to quit after all, we end
up with a black screen.

engines/tetraedge/tetraedge.h

@@ -104,7 +104,8 @@ public:
 			(f == kSupportsLoadingDuringRuntime) ||
 			(f == kSupportsSavingDuringRuntime) ||
 			(f == kSupportsReturnToLauncher) ||
-			(f == kSupportsChangingOptionsDuringRuntime);
+			(f == kSupportsChangingOptionsDuringRuntime) ||
+			(f == kSupportsQuitDialogOverride);
 	};
 
 	bool canLoadGameStateCurrently() override;