Add a notice to the block inspector to indicate how “style” settings work when theme styles are disabled in the editor

[critterverse]

Opening this issue based on some discussion in #32449 around what should happen when changing block styles while the "Use theme styles" option is disabled in the editor (within Preferences -> Appearances). @tellthemachines did a great job explaining some of the complexities around this: #32449 (comment)

While it does feel somewhat like a bug to select a style and see no response, this behavior seems ok to me because it's not the default — by toggling the setting to remove theme styling, one probably expects to lose some degree of WYSIWYG-ness in the editor.

I do think this could potentially be made more clear through a notice that appears at the bottom of Style panels in the inspector when theme styles have been disabled:

The wording could be revised slightly for the Widgets editors until we (potentially) introduce theme styles there. Something to the effect of: Theme styles aren't displayed in the editor but will appear on the front end of your site.

[noisysocks]

Adjusting the labels so as to note that this is an issue with all editors, not just widgets.

It's a little less broken now because Rounded works even with theme styles disabled. I think it might even be good enough that we can close this. I wouldn't really expect that the border options should work without theme styles. What do you think?

Kapture.2022-02-04.at.16.18.15.mp4

[critterverse]

I wouldn't really expect that the border options should work without theme styles.

Agreed, I think turning off the option signals that certain styles won't appear in the editior (but it's great that more are working now).