MM-54399 Move resizable sidebar handles to not overlap scrollbars (#24491)

* MM-54399 Move resizable sidebar handles to not overlap scrollbars

* Disable RHS resizing in mobile view

* Fix snapshots

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Co-authored-by: Mattermost Build <build@mattermost.com>
Co-authored-by: Devin Binnie <devin.binnie@mattermost.com>

webapp/channels/src/sass/components/_post.scss

@@ -1757,7 +1757,6 @@
 
     .post__time,
     .post-preview__time {
-        margin-right: 4px;
         font-size: 0.9em;
         opacity: 0.6;
     }

webapp/channels/src/sass/responsive/_tablet.scss

@@ -404,11 +404,10 @@
                     .post__permalink {
                         position: absolute;
                         top: 2px;
-                        left: -18px;
+                        left: -8px;
 
                         .sidebar--right & {
                             top: 1px;
-                            left: -18px;
                         }
                     }