[Bug]: Theme Editor / Missing Messages Error is not obvious

[wied03]

What happened?

Steps to reproduce

1. Upgrade a FusionAuth installation with missing messages to 1.62.0 (for example, use 1.58.0 as a baseline version).
2. Login to the Admin UI.
3. Navigate to the theme editor in Customizations -> Themes -> Edit.
4. Attempt to make any change to a template and click the Save button.

Expected result

UI calls attention to the fact that messages are missing.

Actual result

UI shows an error message, but it's not clear which left pane (stylesheet, messages, etc.) has the error, and when you click messages, the styling does not indicate it.

Example:

Version

1.62.0

Affects Versions

>= 1.62.0

Alternatives / Workarounds

When saving a theme, if the UI does not return to the list of themes after clicking Save, click each item on the left pane to find out which template (or messages) has the issue.