Disable reference frame invalidation on tvOS and always enable HEVC (for now)

Reference frame invalidation seems to trigger a renderer hang on tvOS 14.5 in my testing.
Since we don't have RFI to bias us toward H.264, let's use HEVC all the time now.

This may change again if the RFI issues are sorted out (perhaps we need to implement
blocking waits for invalidated frames?)

Moonlight TV/Settings.bundle/Root.plist

@@ -156,7 +156,7 @@
 			<key>Key</key>
 			<string>useHevc</string>
 			<key>DefaultValue</key>
-			<false/>
+			<true/>
 		</dict>
 		<dict>
 			<key>Type</key>