[8.13] [Dashboard] Fixes hidden add panel popover on smaller viewports (

#178593) (#178819)

# Backport

This will backport the following commits from `main` to `8.13`:
- [[Dashboard] Fixes hidden add panel popover on smaller viewports
(#178593)](#178593)

<!--- Backport version: 9.4.3 -->

### Questions ?
Please refer to the [Backport tool
documentation](https://github.com/sqren/backport)

<!--BACKPORT [{"author":{"name":"Catherine
Liu","email":"catherine.liu@elastic.co"},"sourceCommit":{"committedDate":"2024-03-15T16:13:54Z","message":"[Dashboard]
Fixes hidden add panel popover on smaller viewports
(#178593)","sha":"be12500902702daadd364f2f2c20685708b989b8","branchLabelMapping":{"^v8.14.0$":"main","^v(\\d+).(\\d+).\\d+$":"$1.$2"}},"sourcePullRequest":{"labels":["Feature:Dashboard","release_note:fix","Team:Presentation","loe:small","impact:critical","v8.14.0","v8.13.1"],"title":"[Dashboard]
Fixes hidden add panel popover on smaller
viewports","number":178593,"url":"https://github.com/elastic/kibana/pull/178593","mergeCommit":{"message":"[Dashboard]
Fixes hidden add panel popover on smaller viewports
(#178593)","sha":"be12500902702daadd364f2f2c20685708b989b8"}},"sourceBranch":"main","suggestedTargetBranches":["8.13"],"targetPullRequestStates":[{"branch":"main","label":"v8.14.0","branchLabelMappingKey":"^v8.14.0$","isSourceBranch":true,"state":"MERGED","url":"https://github.com/elastic/kibana/pull/178593","number":178593,"mergeCommit":{"message":"[Dashboard]
Fixes hidden add panel popover on smaller viewports
(#178593)","sha":"be12500902702daadd364f2f2c20685708b989b8"}},{"branch":"8.13","label":"v8.13.1","branchLabelMappingKey":"^v(\\d+).(\\d+).\\d+$","isSourceBranch":false,"state":"NOT_CREATED"}]}]
BACKPORT-->

Co-authored-by: Catherine Liu <catherine.liu@elastic.co>

src/plugins/dashboard/public/dashboard_app/top_nav/editor_menu.scss

@@ -0,0 +1,6 @@
+.dshSolutionToolbar__editorContextMenu {
+  @include euiScrollBar;
+  @include euiOverflowShadow;
+  max-height: 60vh;
+  overflow-y: scroll;
+}

src/plugins/dashboard/public/dashboard_app/top_nav/editor_menu.tsx

@@ -6,6 +6,8 @@
  * Side Public License, v 1.
  */
 
+import './editor_menu.scss';
+
 import React, { useCallback, useEffect, useMemo, useState, useRef } from 'react';
 import {
   EuiBadge,