[SIEM] Unify Histograms loading states

[patrykkopycinski]

Summary

Implements #55585

• Improve loading states
• Correct color usage

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/siem (Team:SIEM)

[spong]

Checked out, tested locally and performed code review. Thanks for these last few design fixes @patrykkopycinski -- they really clean up the app experience 🙂

LGTM 👍🚀💪

One thing to note, in testing I had an instance where the cursor was stuck as the cursor: default. Not sure if this is on master, but I wasn't able to reproduce either here or there, so we may want to keep any eye out for this in testing.

Cursor stuck as `cursor: default`

Note: Cursor was stuck for all button components, not just inspect as shown below:

[kibanamachine]

💚 Build Succeeded

• continuous-integration/kibana-ci/pull-request
• Commit: 6d4c9ba

History

• 💔 Build #22611 failed a01e032

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