UI: Fix projector on other than primary display

Calling showFullScreen after setGeometry puts the projector on the
expected monitor.  Previously (on FreeBSD, at least) it opened on the
primary display.

UI/window-projector.cpp

@@ -166,8 +166,8 @@ void OBSProjector::SetMonitor(int monitor)
 {
 	savedMonitor = monitor;
 	QScreen *screen = QGuiApplication::screens()[monitor];
-	showFullScreen();
 	setGeometry(screen->geometry());
+	showFullScreen();
 	SetHideCursor();
 }