[Feature] Support parallel unlocking with fingerprint and password

[Jozhin-s-Bazhin]

Currently the locker requires to press enter before being able to authenticate with a fingerprint. This can be solved by running two pam sessions in parallel, like how it's done in hyprlock and gdm.

Relevant hyprlock issue and pull request

[jovanlanik]

Thank you for the relevant hyprlock links. I plan to support this via a module in the future but I'm currently not working on new features in gtklock.