[9.2] [Metrics][Discover] Limit wildcard to 'open' datastreams excluding 'hidden'. (#238947) (#239199)

# Backport

This will backport the following commits from `main` to `9.2`:
- [[Metrics][Discover] Limit wildcard to 'open' datastreams excluding
'hidden'. (#238947)](#238947)

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

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

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Limit wildcard to 'open' datastreams excluding 'hidden'. (#238947)\n\n##
🍒 Summary\n\nThis closes #238875 by only expanding wildcards for
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Limit wildcard to 'open' datastreams excluding 'hidden'. (#238947)\n\n##
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\"open\" datastreams\nwhich will exclude \"hidden\" datastreams. Prior
to this PR the display\nbelow would include metrics
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Limit wildcard to 'open' datastreams excluding 'hidden'. (#238947)\n\n##
🍒 Summary\n\nThis closes #238875 by only expanding wildcards for
\"open\" datastreams\nwhich will exclude \"hidden\" datastreams. Prior
to this PR the display\nbelow would include metrics
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BACKPORT-->

Co-authored-by: Chris Cowan <[email protected]>

Author: kibanamachine

src/platform/plugins/shared/metrics_experience/server/lib/fields/retrieve_fieldcaps.ts

@@ -32,7 +32,7 @@ export async function retrieveFieldCaps({
   // First, resolve the index pattern to get data streams
   const resolveResponse = await esClient.indices.resolveIndex({
     name: indexPattern,
-    expand_wildcards: 'all',
+    expand_wildcards: 'open',
   });
 
   // Extract data stream names