Change in login name ignored

Steps to reproduce:

1. I've been using the test.automotiv@qt.io account for most of my installer testing.
2. I wanted to now switch to my personal account alistair.adams@qt.io. While the maintenance tool is still open I go back to the login screen and change the credentials.
3. Result - I get the same components as per the previous account credentials. When I go back in the installer the old test.automotive credentials are in the the entry boxes.

It would appear the tool is caching the credentials once entered. 

Since restarting the tool with different credentials results in the error message "You seem to have changed the Qt Account which was used for this installation originally. Please use the original credentials (test.automotive@qt.io) for this installation." it would make sense to grey out the box with the login name once the credentials have been accepted and an installation created. This would remove any potential confusion on the user's behalf.