Username regenerates when a user's profile information is edited

[emmajclegg]

When editing a user's profile information on the IATI Publisher Users page, the username field automatically changes.

This auto-generation of username was added to the registration process, but is unexpected behaviour here. The user may be trying to change their name or password - they would not expect their username to change without warning.

Video to illustrate:

Username.regenerating.mp4

Can we prevent username from changing in this form unless the user explicitly makes a change?