Ui improvements and bug fixes (#5677)

* PLT-5565 - Fixing theme colors not updating

* PLT-4721 - Removing status ind for system messages

* PLT-5735 - Fixing ellipsis in firefox

* PLT-5010 - Removing extra space in channel modal

* PLT-5584 - Inline image overrning edit textarea

* PLT-5475  - Fixing tutorials on mobile

* PLT-5142 - Disabling poitner events for status

* PLT-5728 - Fixing emoji highlight on hover

webapp/sass/layout/_post.scss

@@ -3,7 +3,7 @@
 .custom-textarea {
     background: transparent;
     border: 1px solid #cccccc;
-    height: auto;
+    height: 100%;
     line-height: 20px;
     min-height: 36px;
     overflow-x: hidden;
@@ -576,6 +576,12 @@
             }
         }
 
+        &.post--system {
+            .status {
+                visibility: hidden;
+            }
+        }
+
         .post__img {
             padding-top: 0;
         }
@@ -583,6 +589,7 @@
         .status-wrapper {
             cursor: auto;
             height: 14px;
+            pointer-events: none;
 
             .status {
                 bottom: auto;