Convert value provided to PhraseValueInput to string to prevent Exception with numeric values

[kertal]

Summary

Even when a field's format in an Indexpattern is string, a field can contain a number value in _source. Because in _source the value is persisted like it was sent to Elasticsearch. When you add a filter by clicking e.g. in the DocViewer, the value of the field in _source is used for the filter and this causes an Exception when trying to edit the filter (A string value is expected).

Test

Add mapping and data for a new index in Kibana's Console:

PUT test-number
{
  "mappings": {
   
      "properties": {
        "number": {
          "type": "keyword"
        }
      }
    
  }
}

PUT test-number/_doc/1
{
  "number": 123
}

Add an IndexPattern for the test-number index. Switch to Discover, use the new IndexPattern

Add a filter by the number property

Edit the filter.

It works, without this PR, you'd get an Exception

Fixes #30245
Fixes #45010

Checklist

Use strikethroughs to remove checklist items you don't feel are applicable to this PR.

- [ ] This was checked for cross-browser compatibility, including a check against IE11
- [ ] Any text added follows EUI's writing guidelines, uses sentence case text and includes i18n support
- [ ] Documentation was added for features that require explanation or tutorials
- [ ] Unit or functional tests were updated or added to match the most common scenarios
- [ ] This was checked for keyboard-only and screenreader accessibility

For maintainers

- [ ] This was checked for breaking API changes and was labeled appropriately

• This includes a feature addition or change that requires a release note and was labeled appropriately

[elasticmachine]

Pinging @elastic/kibana-app

[Bargs]

LGTM

[TinaHeiligers]

Tested in Chrome, works as expected.
Code LGTM.

[kertal]

thx @TinaHeiligers & @Bargs, here's my personal award to honor your performance in the not yet olympic discipline of synchronous reviewing 🏆

[elasticmachine]

💚 Build Succeeded

• continuous-integration/kibana-ci/pull-request