Block Theme Previews: hide "View" when in the Edit View

[annezazu]

This was raised by @carolinan as part of the FSE Outreach Program's Rapid Revamp call for testing:

Once in edit mode, with the navigation sidebar closed, I found the Activate button in the same area as the save button, but there is also a View site option in the “View” modal next to it, and using that feature shows the currently active theme, not the theme that is being previewed. Perhaps that last option in the View modal could be disabled while previewing.

This refers to the following:

Let's consider hiding this entirely when someone is previewing a theme!

[scruffian]

The other option is to just add the theme_preview parameter to that link so that it actually works as a preview