Replace mask-images with svg components in MessageActionBar (#9088)

* Use svg components in messageactionbar

* highlight options button in pinned messages mock buttons

res/css/views/rooms/_RoomSublist.pcss

@@ -213,7 +213,8 @@ limitations under the License.
         }
 
         &.mx_RoomSublist_resizeBox_forceExpanded .mx_RoomSublist_tiles {
-            // in this state the div can collapse its height entirely in Chromium, so prevent that by allowing overflow
+            // in this state the div can collapse its height entirely in Chromium,
+            // so prevent that by allowing overflow
             overflow: visible;
             // clear the min-height to make it not collapse entirely in a state with no active resizer
             min-height: unset;