[8.x] [ES|QL] Allows the editor suggestions to be visible when inline docs flyout is open (#206064) (#206197)

# Backport

This will backport the following commits from `main` to `8.x`:
- [[ES|QL] Allows the editor suggestions to be visible when inline docs
flyout is open (#206064)](https://github.com/elastic/kibana/pull/206064)

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

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

<!--BACKPORT [{"author":{"name":"Stratoula
Kalafateli","email":"efstratia.kalafateli@elastic.co"},"sourceCommit":{"committedDate":"2025-01-10T07:21:32Z","message":"[ES|QL]
Allows the editor suggestions to be visible when inline docs flyout is
open (#206064)\n\n## Summary\r\n\r\nCloses
https://github.com/elastic/kibana/issues/199299\r\n\r\nChanges the
flyout z-index in order the suggestions to be visible when\r\nthe docs
are
open.\r\n\r\n\r\n![image\r\n(75)](https://github.com/user-attachments/assets/e13595d0-e98c-4e7b-9673-a6e3d011fee7)","sha":"feefa776689c09c0664242d24c667ba42dc56ce7","branchLabelMapping":{"^v9.0.0$":"main","^v8.18.0$":"8.x","^v(\\d+).(\\d+).\\d+$":"$1.$2"}},"sourcePullRequest":{"labels":["release_note:fix","v9.0.0","Feature:ES|QL","Team:ESQL","backport:version","v8.18.0"],"title":"[ES|QL]
Allows the editor suggestions to be visible when inline docs flyout is
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Allows the editor suggestions to be visible when inline docs flyout is
open (#206064)\n\n## Summary\r\n\r\nCloses
https://github.com/elastic/kibana/issues/199299\r\n\r\nChanges the
flyout z-index in order the suggestions to be visible when\r\nthe docs
are
open.\r\n\r\n\r\n![image\r\n(75)](https://github.com/user-attachments/assets/e13595d0-e98c-4e7b-9673-a6e3d011fee7)","sha":"feefa776689c09c0664242d24c667ba42dc56ce7"}},"sourceBranch":"main","suggestedTargetBranches":["8.x"],"targetPullRequestStates":[{"branch":"main","label":"v9.0.0","branchLabelMappingKey":"^v9.0.0$","isSourceBranch":true,"state":"MERGED","url":"https://github.com/elastic/kibana/pull/206064","number":206064,"mergeCommit":{"message":"[ES|QL]
Allows the editor suggestions to be visible when inline docs flyout is
open (#206064)\n\n## Summary\r\n\r\nCloses
https://github.com/elastic/kibana/issues/199299\r\n\r\nChanges the
flyout z-index in order the suggestions to be visible when\r\nthe docs
are
open.\r\n\r\n\r\n![image\r\n(75)](https://github.com/user-attachments/assets/e13595d0-e98c-4e7b-9673-a6e3d011fee7)","sha":"feefa776689c09c0664242d24c667ba42dc56ce7"}},{"branch":"8.x","label":"v8.18.0","branchLabelMappingKey":"^v8.18.0$","isSourceBranch":false,"state":"NOT_CREATED"}]}]
BACKPORT-->

Co-authored-by: Stratoula Kalafateli <efstratia.kalafateli@elastic.co>

src/platform/packages/private/kbn-language-documentation/src/components/as_flyout/index.tsx

@@ -81,6 +81,7 @@ function DocumentationFlyout({
           onClose={() => onHelpMenuVisibilityChange(false)}
           aria-labelledby="esqlInlineDocumentationFlyout"
           data-test-subj="esqlInlineDocumentationFlyout"
+          css={{ zIndex: 1 }}
           type="push"
           size={DEFAULT_WIDTH}
           paddingSize="m"