ref: remove grayscale filter from participants thumbnails

css/_videolayout_default.scss

         visibility: hidden;
         z-index: $zindex2;
     }
-
-    &.audio-only {
-        .videoThumbnailProblemFilter {
-            filter: none;
-        }
-    }
 }
 
 #localVideoWrapper {
     filter: grayscale(.5) opacity(0.8);
 }
 
-.videoThumbnailProblemFilter {
-    -webkit-filter: grayscale(100%);
-    filter: grayscale(100%);
-}
-
 #remotePresenceMessage,
 #remoteConnectionMessage {
     position: absolute;

modules/UI/videolayout/RemoteVideo.js

         // Update 'mutedWhileDisconnected' flag
         this._figureOutMutedWhileDisconnected();
         this.updateConnectionStatus(connectionStatus);
-
-        const isInterrupted = connectionStatus === JitsiParticipantConnectionStatus.INTERRUPTED;
-
-        // Toggle thumbnail video problem filter
-
-        this.selectVideoElement().toggleClass('videoThumbnailProblemFilter', isInterrupted);
-        this.$avatar().toggleClass('videoThumbnailProblemFilter', isInterrupted);
     }
 
     /**