sounds: lower log severity

When native SDK users end a meeting the view gets disposed and detached from
React, and then the entire app gets destroyed and these errors get printed at
the error level, throwing some people off.

react/features/base/sounds/reducer.js

@@ -96,10 +96,7 @@ function _addOrRemoveAudioElement(state, action) {
                 }));
         }
     } else {
-        const actionName
-            = isAddAction ? '_ADD_AUDIO_ELEMENT' : '_REMOVE_AUDIO_ELEMENT';
-
-        logger.error(`${actionName}: no sound for id: ${soundId}`);
+        logger.warn(`${action.type}: no sound for id: ${soundId}`);
     }
 
     return nextState;