UI: Check current affinity before calling SetWindowDisplayAffinity

For some reason, SetWindowDisplayAffinity can make windows visible even
when it sets the same value for affinity that GetWindowDisplayAffinity
reports. Possibly an API bug as this is probably not a widely used API
yet?

Fixes a weird window with no size appearing when browsing for files on
Windows.

UI/window-basic-main.cpp

@@ -9964,10 +9964,14 @@ void OBSBasic::SetDisplayAffinity(QWindow *window)
 #ifdef _WIN32
 	HWND hwnd = (HWND)window->winId();
 
-	if (hideFromCapture)
-		SetWindowDisplayAffinity(hwnd, WDA_EXCLUDEFROMCAPTURE);
-	else
-		SetWindowDisplayAffinity(hwnd, WDA_NONE);
+	DWORD curAffinity;
+	if (GetWindowDisplayAffinity(hwnd, &curAffinity)) {
+		if (hideFromCapture && curAffinity != WDA_EXCLUDEFROMCAPTURE)
+			SetWindowDisplayAffinity(hwnd, WDA_EXCLUDEFROMCAPTURE);
+		else if (curAffinity != WDA_NONE)
+			SetWindowDisplayAffinity(hwnd, WDA_NONE);
+	}
+
 #else
 // TODO: Implement for other platforms if possible. Don't forget to
 // implement SetDisplayAffinitySupported too!