update (_sidebar-right.scss): remove default max-width (400px) of .sidebar--right (#24878)

webapp/channels/src/sass/layout/_sidebar-right.scss

@@ -17,7 +17,6 @@
 
     &:not(.expanded):not(.resize-disabled) {
         min-width: 400px;
-        max-width: 400px;
 
         &.sidebar--right--width-holder {
             @media screen and (min-width: 901px) and (max-width: 1200px) {