Do not call showContentNotSupportedIfNeeded multiple times

Author: Stypox

app/src/main/java/org/schabi/newpipe/fragments/list/channel/ChannelFragment.java

@@ -532,6 +532,7 @@ public void handleResult(@NonNull final ChannelInfo result) {
             if (throwable instanceof ContentNotSupportedException) {
                 channelContentNotSupported = true;
                 showContentNotSupportedIfNeeded();
+                break;
             }
         }