gtklock: Fix screen goes black after wrong passwords

[vunnyso]

Description of changes

This patch will fix SP-4849 issue.

Checklist for things done

• [x] Summary of the proposed changes in the PR description
• [x] More detailed description in the commit message(s)
• [x] Commits are squashed into relevant entities - avoid a lot of minimal dev time commits in the PR
• [x] Contribution guidelines followed
• [ ] Ghaf documentation updated with the commit - https://tiiuae.github.io/ghaf/
• [ ] PR linked to architecture documentation and requirement(s) (ticket id)
• [x] Test procedure described (or includes tests). Select one or more:
  • [x] Tested on Lenovo X1 x86_64
  • [ ] Tested on Jetson Orin NX or AGX aarch64
  • [ ] Tested on Polarfire riscv64
• [ ] Author has run nix flake check --accept-flake-config and it passes
• [x] All automatic Github Action checks pass - see actions
• [x] Author has added reviewers and removed PR draft status

Testing

Testing instructions in SP-4849

[vunnyso]

As discussed with @vadika, he suggested to merge the partial fix as of now. We can update with proper fix once its available in https://github.com/jovanlanik/gtklock/issues/101

[vunnyso]

Code is OK.

Tested on X1: The messages are in a box and doesn't overflow. But screen still goes black after many attempts, but the limit seems to be higher.

Thanks @humaidq-tii for testing, appreciate your help. Yes if we try too many attempts there was race case possibility before which was resulting in coredump and was fixed in gtklock repo but was not included in release. Now I have included that patch as well. I don't see any black screen on my side (Tested on X1).

[johannarautanen]

lenovo x1, booted ghaf from SSD memory card:

No more black screen while entering lost of wrong passwords and fingerprints.

There is no scroll bar visible for the failure-texts and cannot "close" the failure-texts, that issues will be handled in https://github.com/jovanlanik/gtklock/issues/101

• automated tests: ok
• all apps launched manually ok