[Portal] User picture doesn't use active domain

**Describe the bug**
Despite being correct in the user info endpoint and the API, the portal doesn't display the user profile picture correctly because it is still pointing to the domain created originally, instead of the active custom one.

**Authgear Version**
2026-07-30.0

**To Reproduce**
Pre-requisite: having an active custom domain that is different from the originally created.
1. Go to "Users"
2. Open a user
3. See that the user image is broken (in case the original domain isn't point anywhere) and that the profile picture URL references the original domain and not the custom one.

**Expected behavior**
Expected to use the active domain for the project.

**Screenshots**
If applicable, add screenshots to help explain your problem.

**Client Env (if applicable, please complete the following information):**
- Device: Desktop
- OS: macOS 27 Golden Gate
- Browser: Safari
- Browser Version: 27

**Additional context**
Add any other context about the problem here.

No file or test is named. Reproduce the broken image from the Portal Users page with an active custom domain, then trace where the user profile-picture URL is constructed. Done means the URL uses the project's active domain and the image loads instead of referencing the originally created domain.

Written by the indexing model from the issue text.