crash: run platform compat hooks in crash reporter init

For some reason, QtWayland crashes we work around trigger in this
path. This was previously masked when the crash reporter didn't unmask
signals, as long as the original process crashed with SIGSEGV.

src/wayland/init.cpp

@@ -33,8 +33,9 @@ class WaylandPlugin: public QsEnginePlugin {
 		return isWayland;
 	}
 
+	void preinit() override { installWlProxySafeDeref(); }
+
 	void init() override {
-		installWlProxySafeDeref();
 		installPlatformMenuHook();
 		installPopupPositioner();
 	}