Google Photos Activity Log is unthemed

### Is there an existing issue outlining your problem?

- [x] I am using the latest version of the provided userstyle.
- [x] I have searched the existing issues and they do not solve my problem.

### What userstyles are you seeing the problem on?

lbl:google-photos

### Describe your problem.

Activity Log in Google Photos is completely unthemed. This was an unintentional regression during #1724 that I didn't catch.

### Attach screenshots.

### What browser(s) are you seeing the problem on?

Chrome 139.0.7258.154

### Any additional comments?

_No response_

No file or test is named. Start with the lbl:google-photos userstyle and reproduce the issue in Google Photos using Chrome, then inspect the Activity Log styles. Done means the Activity Log is visibly themed consistently with the rest of Google Photos.

Written by the indexing model from the issue text.