[EuiCodeEditor] Console error when using the editor without import the default theme

[alexwizp]

Summary

In #2970 the default value for the theme was set to github. As a result, now we have many places in Kibana where we need to import this theme even if we don't want to specify theme (remind you it's optional property).

Related issue in Kibana repo:
elastic/kibana#56424

I think if we decided to set github as a default theme, it should be loaded here

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]

Thanks for the background & fix!

Can you please add a bugfix changelog entry to CHANGELOG.md referencing this PR? After that, this will be good to merge

[chandlerprall]

After a slack conversation with the team, instead of defaulting to github we should go back to passing an undefined theme by default - EUI applies some custom style rules in our CSS build, rather than through brace's theme configuration.

[alexwizp]

@chandlerprall is not sure we should pass undefined because this will return the problem of why the default value was added. My suggestion is to set the textmate theme, because this is the default theme for the Brace editor

[chandlerprall]

The previous PR's goal was adding documentation around the theme prop, changing the default was secondary and probably wasn't the right thing to merge with. I like your update to textmate, and confirmed everything locally runs without errors when using only those defaults.

undefined would be fine as textmate is still the underlying default, but being explicit here helps readability