added enter key functionality

[anishagg17]

Summary

Fixes : #3033
added enter key functionality in eui super date picker

Checklist

- [ ] Check against all themes for compatibility in both light and dark modes
- [ ] Checked in mobile
- [ ] Checked in IE11 and Firefox
- [ ] Props have proper autodocs
- [ ] Added documentation examples

• Added or updated jest tests
  - [ ] Checked for breaking changes and labeled appropriately
• Checked for accessibility including keyboard-only and screenreader modes
• A changelog entry exists and is marked appropriately

[kibanamachine]

Since this is a community submitted pull request, a Jenkins build has not been kicked off automatically. Can an Elastic organization member please verify the contents of this patch and then kick off a build manually?

[chandlerprall]

Functionality works as desired; have some feedback on the code changes

[chandlerprall]

@myasonik can you please review the change of <fieldset> -> <fieldset role="presentation" onKeyDown={this.handleKeyDown}> in both refresh_interval.js and quick_select.js ? See comments in #3048 (comment)

Alternative would be to pass the onKeyDown individually on the inputs, but this grouping at the fieldset seems decent?

[anishagg17]

this function performs the following :

[myasonik]

jenkins test this

[kibanamachine]

Preview documentation changes for this PR: https://eui.elastic.co/pr_3048/

[anishagg17]

All changes have been made

[chandlerprall]

jenkins test this

[kibanamachine]

Preview documentation changes for this PR: https://eui.elastic.co/pr_3048/

[chandlerprall]

Changes LGTM; thanks for iterating on this one @anishagg17 !