chore: Improve layout styles (#12025)

# Pull Request Template

## Description

This PR fixes the layout overflow scroll issue and removes unused CSS.
It also optimizes the display of the Sidebar, Copilot Panel, and
Conversation Panel in the mobile view.
Additionally, it resolves a runtime console warning.

## Type of change

- [x] Bug fix (non-breaking change which fixes an issue)

## How Has This Been Tested?

### Screencast


https://github.com/user-attachments/assets/7e8885fa-6174-4740-80f1-bb1cec6517fc




## Checklist:

- [x] My code follows the style guidelines of this project
- [x] I have performed a self-review of my code
- [x] I have commented on my code, particularly in hard-to-understand
areas
- [ ] I have made corresponding changes to the documentation
- [x] My changes generate no new warnings
- [ ] I have added tests that prove my fix is effective or that my
feature works
- [x] New and existing unit tests pass locally with my changes
- [ ] Any dependent changes have been merged and published in downstream
modules

---------

Co-authored-by: Muhsin Keloth <muhsinkeramam@gmail.com>

app/javascript/dashboard/assets/scss/_woot.scss

@@ -37,30 +37,6 @@ body {
   width: 100%;
 }
 
-.app-wrapper {
-  @apply h-screen flex-grow-0 min-h-0 w-full;
-
-  .button--fixed-top {
-    @apply fixed ltr:right-2 rtl:left-2 top-2 flex flex-row;
-  }
-}
-
-.banner + .app-wrapper {
-  // Reduce the height of the dashboard to make room for the banner.
-  // And causing the top right green-action button to be pushed down when scrolling.
-  @apply h-[calc(100%-48px)];
-
-  .button--fixed-top {
-    @apply top-14;
-  }
-
-  .off-canvas-content {
-    .button--fixed-top {
-      @apply top-2;
-    }
-  }
-}
-
 .tooltip {
   @apply bg-n-solid-2 text-n-slate-12 py-1 px-2 z-40 text-xs rounded-md max-w-96;
 }