Fix crash when viewing Playlists with rates outside the Calc range

0.7x to 3.0x are the only calculated values and things outside this range just kind of crash the game in a lot of places because of that

src/Etterna/Singletons/SongManager.cpp

@@ -539,7 +539,9 @@ Playlist::GetAverageRating()
 	int numloaded = 0;
 	for (auto& n : chartlist) {
 		if (n.loaded) {
-			o += n.stepsptr->GetMSD(n.rate, 0);
+			auto rate = n.rate;
+			CLAMP(rate, 0.7f, 3.f);
+			o += n.stepsptr->GetMSD(rate, 0);
 			++numloaded;
 		}
 	}