[8.x] Display error banner instead of warning (#195913) (#196344)

# Backport

This will backport the following commits from `main` to `8.x`:
- [Display error banner instead of warning
(#195913)](https://github.com/elastic/kibana/pull/195913)

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

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

<!--BACKPORT [{"author":{"name":"Sonia Sanz
Vivas","email":"sonia.sanzvivas@elastic.co"},"sourceCommit":{"committedDate":"2024-10-15T15:11:23Z","message":"Display
error banner instead of warning (#195913)\n\nCloses
[110155](https://github.com/elastic/kibana/issues/110155)\r\n\r\n##
Summary\r\nWhen the remote cluster creation has an error the banner
displayed was a\r\nwarning instead of an error.\r\n\r\n### How to
reproduce?\r\n1.) Navigate to Remote Clusters\r\n2.) Create a new Remote
Cluster\r\n3.) Add information for a cluster except set the max number
of\r\nconnections to 999999999999999999\r\n4.) Try to save.\r\n\r\n###
Testing\r\nNo testing since this doesn't change any
functionality.\r\n\r\n<img width=\"1243\"
alt=\"110155\"\r\nsrc=\"https://github.com/user-attachments/assets/802aa9f3-f70a-44da-a135-8187ada2e78a\">","sha":"ded274062ca55e78a79973704c2c0e8814516c2b","branchLabelMapping":{"^v9.0.0$":"main","^v8.16.0$":"8.x","^v(\\d+).(\\d+).\\d+$":"$1.$2"}},"sourcePullRequest":{"labels":["Feature:CCR
and Remote Clusters","Team:Kibana
Management","release_note:skip","v9.0.0","backport:prev-minor","v8.16.0"],"title":"Display
error banner instead of
warning","number":195913,"url":"https://github.com/elastic/kibana/pull/195913","mergeCommit":{"message":"Display
error banner instead of warning (#195913)\n\nCloses
[110155](https://github.com/elastic/kibana/issues/110155)\r\n\r\n##
Summary\r\nWhen the remote cluster creation has an error the banner
displayed was a\r\nwarning instead of an error.\r\n\r\n### How to
reproduce?\r\n1.) Navigate to Remote Clusters\r\n2.) Create a new Remote
Cluster\r\n3.) Add information for a cluster except set the max number
of\r\nconnections to 999999999999999999\r\n4.) Try to save.\r\n\r\n###
Testing\r\nNo testing since this doesn't change any
functionality.\r\n\r\n<img width=\"1243\"
alt=\"110155\"\r\nsrc=\"https://github.com/user-attachments/assets/802aa9f3-f70a-44da-a135-8187ada2e78a\">","sha":"ded274062ca55e78a79973704c2c0e8814516c2b"}},"sourceBranch":"main","suggestedTargetBranches":["8.x"],"targetPullRequestStates":[{"branch":"main","label":"v9.0.0","branchLabelMappingKey":"^v9.0.0$","isSourceBranch":true,"state":"MERGED","url":"https://github.com/elastic/kibana/pull/195913","number":195913,"mergeCommit":{"message":"Display
error banner instead of warning (#195913)\n\nCloses
[110155](https://github.com/elastic/kibana/issues/110155)\r\n\r\n##
Summary\r\nWhen the remote cluster creation has an error the banner
displayed was a\r\nwarning instead of an error.\r\n\r\n### How to
reproduce?\r\n1.) Navigate to Remote Clusters\r\n2.) Create a new Remote
Cluster\r\n3.) Add information for a cluster except set the max number
of\r\nconnections to 999999999999999999\r\n4.) Try to save.\r\n\r\n###
Testing\r\nNo testing since this doesn't change any
functionality.\r\n\r\n<img width=\"1243\"
alt=\"110155\"\r\nsrc=\"https://github.com/user-attachments/assets/802aa9f3-f70a-44da-a135-8187ada2e78a\">","sha":"ded274062ca55e78a79973704c2c0e8814516c2b"}},{"branch":"8.x","label":"v8.16.0","branchLabelMappingKey":"^v8.16.0$","isSourceBranch":false,"state":"NOT_CREATED"}]}]
BACKPORT-->

Co-authored-by: Sonia Sanz Vivas <sonia.sanzvivas@elastic.co>

x-pack/plugins/remote_clusters/public/application/sections/components/remote_cluster_form/remote_cluster_form.tsx

@@ -423,7 +423,7 @@ export class RemoteClusterForm extends Component<Props, State> {
 
       return (
         <Fragment>
-          <EuiCallOut title={message} iconType="cross" color="warning">
+          <EuiCallOut title={message} color="danger" iconType="error">
             {errorBody}
           </EuiCallOut>