mgr/dashboard: Fix banner and scroll issue

- includes fix to make banner visible again
- includes fix to allow scrolling on longer pages like, expand cluster and upgrade

Fixes https://tracker.ceph.com/issues/67795

Signed-off-by: Afreen Misbah <[email protected]>

Author: afreen23

src/pybind/mgr/dashboard/frontend/src/app/core/layouts/workbench-layout/workbench-layout.component.scss

@@ -10,7 +10,7 @@
 .container-fluid {
   overflow: auto;
   padding-bottom: 100px;
-  top: 48px;
+  padding-top: 48px;
 }
 
 .rgw-dashboard {