Remove unused ProfileXhr

What does this MR do?

Removes unused xhr legacy code

How confident are you it won't break things if deployed?

Confident. The xhr methods themselves were broken anyway for quite some time now.

Checklist

• added a test, or explain why one is not needed/possible... (no new code)
• no unrelated changes
• asked someone for a code review
• set a "for:" label to indicate who will be affected by this change
• added to the next milestone (see https://gitlab.com/foodsharing-dev/foodsharing/-/milestones, unless it has a "for:Dev" label)
• added an entry to CHANGELOG.md