Assign functional tests and example plugins code ownership to Data Discovery (#162740)

## Summary

This PR assigns code ownership to the Data Discovery team for various
functional tests as well as a couple of example plugins. All of the
tests assigned to us in `CODEOWNERS` currently have no one else assigned
to them.

### Checklist

- [ ] ~Any text added follows [EUI's writing
guidelines](https://elastic.github.io/eui/#/guidelines/writing), uses
sentence case text and includes [i18n
support](https://github.com/elastic/kibana/blob/main/packages/kbn-i18n/README.md)~
- [ ]
~[Documentation](https://www.elastic.co/guide/en/kibana/master/development-documentation.html)
was added for features that require explanation or tutorials~
- [ ] ~[Unit or functional
tests](https://www.elastic.co/guide/en/kibana/master/development-tests.html)
were updated or added to match the most common scenarios~
- [ ] ~Any UI touched in this PR is usable by keyboard only (learn more
about [keyboard
accessibility](https://webaim.org/techniques/keyboard/))~
- [ ] ~Any UI touched in this PR does not create any new axe failures
(run axe in browser:
[FF](https://addons.mozilla.org/en-US/firefox/addon/axe-devtools/),
[Chrome](https://chrome.google.com/webstore/detail/axe-web-accessibility-tes/lhdoppojpmngadmnindnejefpokejbdd?hl=en-US))~
- [ ] ~If a plugin configuration key changed, check if it needs to be
allowlisted in the cloud and added to the [docker
list](https://github.com/elastic/kibana/blob/main/src/dev/build/tasks/os_packages/docker_generator/resources/base/bin/kibana-docker)~
- [ ] ~This renders correctly on smaller devices using a responsive
layout. (You can test this [in your
browser](https://www.browserstack.com/guide/responsive-testing-on-local-server))~
- [ ] ~This was checked for [cross-browser
compatibility](https://www.elastic.co/support/matrix#matrix_browsers)~

### For maintainers

- [ ] This was checked for breaking API changes and was [labeled
appropriately](https://www.elastic.co/guide/en/kibana/master/contributing.html#kibana-release-notes-process)

---------

Co-authored-by: kibanamachine <42973632+kibanamachine@users.noreply.github.com>

examples/data_view_field_editor_example/kibana.jsonc

@@ -1,16 +1,12 @@
 {
   "type": "plugin",
   "id": "@kbn/data-view-field-editor-example-plugin",
-  "owner": "@elastic/kibana-app-services",
+  "owner": "@elastic/kibana-data-discovery",
   "description": "Data view field editor example app",
   "plugin": {
     "id": "dataViewFieldEditorExample",
     "server": false,
     "browser": true,
-    "requiredPlugins": [
-      "data",
-      "dataViewFieldEditor",
-      "developerExamples"
-    ]
+    "requiredPlugins": ["data", "dataViewFieldEditor", "developerExamples"]
   }
 }