Profile picture doesn't upload

### Steps to reproduce

1. Click on top right avatar
2. Click on your username in the pop up menu
3. Click the pen icon on the profile picture
4. Choose an image

### Outcome

#### What did you expect?
Profile picture is uploaded, probably?

#### What happened instead?
Nothing

It does submit if you edit the display name field (eg. delete & retype the last character)

### Operating system

_No response_

### Browser information

_No response_

### URL for webapp

_No response_

### Will you send logs?

No

Start by reproducing the profile-picture flow: open the avatar menu, visit the username, select the pen icon, and choose an image. Trace the profile form and image-upload handling from there; done means selecting an image submits the change and the new profile picture appears without editing the display name.

Written by the indexing model from the issue text.