MM-55438 Fix app bar divider (#25425)

* Fix spacing before the app bar divider

* Adjust bottom margin

* Fix lint

* Align appbar lines

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Co-authored-by: Mattermost Build <build@mattermost.com>

webapp/channels/src/components/app_bar/app_bar.scss

@@ -24,7 +24,7 @@ $app-bar-width: 48px;
         width: $app-bar-width;
         flex: 1;
         flex-flow: column;
-        padding-top: 16px;
+        padding-top: 19px;
         background-color: rgba(var(--center-channel-color-rgb), 0.04);
         -ms-overflow-style: none;
         overflow-x: hidden;
@@ -122,8 +122,8 @@ $app-bar-width: 48px;
         .app-bar__divider {
             width: 28px;
             border-top: 1px solid rgba(var(--center-channel-color-rgb), 0.16);
-            margin-top: 14px;
-            margin-bottom: 14px;
+            margin-top: 0;
+            margin-bottom: 19px;
         }
 
         .app-bar__icon.channel-header__icon--active {