fix(Thumbnails): removes unused css classes

index.html

             </div>
             <div class="filmstrip">
                 <div class="filmstrip__videos" id="remoteVideos">
-                    <span id="localVideoContainer" class="videocontainer videocontainer_small">
+                    <span id="localVideoContainer" class="videocontainer">
                         <div class="videocontainer__background"></div>
                         <span id="localVideoWrapper">
                             <!--<video id="localVideo" autoplay muted></video> - is now per stream generated -->

modules/UI/videolayout/RemoteVideo.js

 RemoteVideo.createContainer = function (spanId) {
     let container = document.createElement('span');
     container.id = spanId;
-    container.className = 'videocontainer videocontainer_remote';
+    container.className = 'videocontainer';
 
     let wrapper = document.createElement('div');
     wrapper.className = 'videocontainer__background';