(only flatpak version) Adding project crashes if "existing user" is chosen and wrong email OR wrong password is provided.

Version 8.2.12 Flatpak running under proper Wayland (not Xwayland)
I have been testing snap & flatpak versions.
These results come from an aarch64 host and a x86_64 (intel) host

Launch with `flatpak run edu.berkeley.BOINC &`
The latest flatpak version consistently crashes if i :
Try to add a project via the menu option
Choose "Existing User"
Provide either an email that is not a current user OR a correct current user email with an incorrect password.

The "Add Project" module hangs for a while and then will show "Application is not responding" - Force Quit or Wait
The "Wait" option does not work (left it for a night)
Only option out is "Force Quit" which leaves boinc-client running.

The snap/edge version (8.3.x) on the same hosts does not show this behaviour.
It will show an error from the project server and a "Finish" button in the dialog.

Start by running `flatpak run edu.berkeley.BOINC &` on Wayland and reproduce the Add Project flow with an unknown email or an incorrect password. Compare the Flatpak behavior with the snap/edge version; done means invalid credentials produce a project-server error and a usable Finish option instead of the module hanging and the application becoming unresponsive.

Written by the indexing model from the issue text.