[9.1] Wrap Add Rule button in div to prevent flex (elastic#231551) (elastic#231698)

# Backport

This will backport the following commits from `main` to `9.1`:
- [Wrap Add Rule button in div to prevent flex
(elastic#231551)](elastic#231551)

<!--- Backport version: 9.6.6 -->

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

<!--BACKPORT
[{"author":{"name":"Kurt","email":"[email protected]"},"sourceCommit":{"committedDate":"2025-08-13T19:08:54Z","message":"Wrap
Add Rule button in div to prevent flex (elastic#231551)\n\n## Summary\n\nCloses
https://github.com/elastic/kibana/issues/221857\n\n\nhttps://eui.elastic.co/docs/components/layout/flex/item/#flex-items-are-also-flex\n\n<img
width=\"1299\" height=\"446\" alt=\"Screenshot 2025-08-12 at 5 50
04 PM\"\nsrc=\"https://github.com/user-attachments/assets/4e1632f8-4a89-44fd-98f6-86e154c79512\"\n/>\n\n\n##
Testing\n\nStart KB/ES > navigate to Role Mapping Screen > Click \"Add
Rule\" >\nNotice Popover is correctly anchored\n\n## Release note\nFixed
positioning of the \"Add rule\" popover on the Role Mappings
page","sha":"579477371a492cecba3457de20afffce4b7d0e71","branchLabelMapping":{"^v9.2.0$":"main","^v(\\d+).(\\d+).\\d+$":"$1.$2"}},"sourcePullRequest":{"labels":["chore","release_note:fix","Team:Security","backport:all-open","v9.2.0"],"title":"Wrap
Add Rule button in div to prevent
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Add Rule button in div to prevent flex (elastic#231551)\n\n## Summary\n\nCloses
https://github.com/elastic/kibana/issues/221857\n\n\nhttps://eui.elastic.co/docs/components/layout/flex/item/#flex-items-are-also-flex\n\n<img
width=\"1299\" height=\"446\" alt=\"Screenshot 2025-08-12 at 5 50
04 PM\"\nsrc=\"https://github.com/user-attachments/assets/4e1632f8-4a89-44fd-98f6-86e154c79512\"\n/>\n\n\n##
Testing\n\nStart KB/ES > navigate to Role Mapping Screen > Click \"Add
Rule\" >\nNotice Popover is correctly anchored\n\n## Release note\nFixed
positioning of the \"Add rule\" popover on the Role Mappings
page","sha":"579477371a492cecba3457de20afffce4b7d0e71"}},"sourceBranch":"main","suggestedTargetBranches":[],"targetPullRequestStates":[{"branch":"main","label":"v9.2.0","branchLabelMappingKey":"^v9.2.0$","isSourceBranch":true,"state":"MERGED","url":"https://github.com/elastic/kibana/pull/231551","number":231551,"mergeCommit":{"message":"Wrap
Add Rule button in div to prevent flex (elastic#231551)\n\n## Summary\n\nCloses
https://github.com/elastic/kibana/issues/221857\n\n\nhttps://eui.elastic.co/docs/components/layout/flex/item/#flex-items-are-also-flex\n\n<img
width=\"1299\" height=\"446\" alt=\"Screenshot 2025-08-12 at 5 50
04 PM\"\nsrc=\"https://github.com/user-attachments/assets/4e1632f8-4a89-44fd-98f6-86e154c79512\"\n/>\n\n\n##
Testing\n\nStart KB/ES > navigate to Role Mapping Screen > Click \"Add
Rule\" >\nNotice Popover is correctly anchored\n\n## Release note\nFixed
positioning of the \"Add rule\" popover on the Role Mappings
page","sha":"579477371a492cecba3457de20afffce4b7d0e71"}}]}] BACKPORT-->

Co-authored-by: Kurt <[email protected]>

Author: kibanamachine

x-pack/platform/plugins/shared/security/public/management/role_mappings/edit_role_mapping/rule_editor_panel/rule_group_editor.tsx

@@ -77,7 +77,9 @@ export class RuleGroupEditor extends Component<Props, {}> {
           {this.renderSubRules()}
           {this.props.allowAdd && this.props.readOnly === false && (
             <EuiFlexItem>
-              <AddRuleButton onClick={this.onAddRuleClick} />
+              <div>
+                <AddRuleButton onClick={this.onAddRuleClick} />
+              </div>
             </EuiFlexItem>
           )}
         </EuiFlexGroup>