User dropdown “Profile” redirects to 404 when Indigo is not used

[magajh]

Description

We found (via client error reports) that when an instance is not using the Indigo theme, the redirect from legacy pages to the Profile page fails and lands on a 404.

The problem is how the profile URL in the user dropdown is being constructed. It forms and incorrect url due to how urljoin is applied when forming the MFE target (explained in more detail in the PR)

There is already a proposed fix that aligns the URL construction with the approach used by Indigo and is also compatible with Tutor MFE’s URL configuration. It’s a small, targeted change: #37416

Steps to Reproduce

• Log in on an instance without the Indigo theme.
• From a legacy page (e.g., Course Catalog), open the user menu and click Profile
• Observe the redirect and final URL → results in 404.

[magajh]

It would be great to merge this before the cut of Ulmo. We already have an approval, but we’d like another one before merging

[felipemontoya]

The fix was merged this morning after two more approvals came in.