fix(theming): Stop leaking user theme into capabilities

[provokateurin]

Summary

The capabilities were mixing the admin theme and the user theme. For now I set to only use the admin theming, but I intend to submit a second fix that uses the user theme if a the request came from a logged in user.

Checklist

• Code is properly formatted
• Sign-off message is added to all commits
• Tests (unit, integration, api and/or acceptance) are included
• Screenshots before/after for front-end changes
• Documentation (manuals or wiki) has been updated or is not required
• Backports requested where applicable (ex: critical bugfixes)

[juliusknorr]

Might need some alignment between @nextcloud/designers and @tobiasKaminsky as those capabilities are used to style the clients. I would still expect the user colors in there

[provokateurin]

I agree that the user theming should be exposed in the capabilities. I intend to implement that, but currently the capabilities expose a mix of user and admin theming.

[szaimen]

I agree that the user theming should be exposed in the capabilities. I intend to implement that, but currently the capabilities expose a mix of user and admin theming.

If this will be done in a follow-up, I'd say this PR is fine from design perspective 👍

[tobiasKaminsky]

Right now I see no change for clients.
If this is true, I am fine with it :)

[susnux]

@provokateurin Drone errors are related.
I think you have to fix apps/theming/tests/CapabilitiesTest.php

[provokateurin]

Yes I know, I just didn't have the time yet :)

[provokateurin]

I think the drone failure now is unrelated. Can someone confirm and possibly give it a force merge?

[provokateurin]

Closed in favor of #41059