[MM-42752] Channel header icons impacted by long channel name in mobile view (#25450)

webapp/channels/src/sass/layout/_navigation.scss

@@ -85,8 +85,8 @@
 
         .navbar-toggle {
             z-index: 5;
-            width: 50px;
             height: 50px;
+            flex: 0 0 50px;
             padding: 0 10px;
             border-width: 0;
             border-color: transparent;
@@ -98,8 +98,8 @@
 
             &.navbar-right__icon {
                 display: flex;
-                width: 32px;
                 height: 32px;
+                flex: 0 0 32px;
                 align-items: center;
                 justify-content: center;
                 padding: 0;