make config check for new Theme bundles. refs #1935

I don't know if this fully completes the ticket, but it addresses the two issues that were reported as far as I can see.

ping @cmfcmf

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | -
| Refs tickets  | #1935
| License       | MIT
| Doc PR        | -