Multiple Ui improvements (#4767)

* PLT-4911 - Adding new target for OAuth help links

* PLT-4953 - Fixing styles for the unread messages indicator

* PLT-4901 - Fixing header modal overlap on mobile

* PLT-4916 - Swapping position of edit and delete

webapp/sass/responsive/_mobile.scss

@@ -44,6 +44,11 @@
             color: $white;
             font-size: 15px;
             padding: 15px 20px 100px;
+
+            > div {
+                height: calc(100vh - 150px);
+                overflow: auto;
+            }
         }
 
         .close {