[3.20] community/onboard: fix GIL for obj alloc & fix sticking key

cherry-picked from MR !69240 (merged).

This introduced a patch from Azkali, which fixes the issue of onboard crashing when pressing a key.

Another patch is from Linux Mint, which fixes the issue of sticking key.

Link: https://gitlab.com/postmarketOS/pmaports/-/issues/2888

Link: https://bugs.launchpad.net/ubuntu/+source/onboard/+bug/2063041

Link: https://github.com/Azkali/onboard-keyman/commit/ac8633670a5467e7b7364651e77be2c94f7e3104.patch

Link: https://gitlab.com/mint-pins/onboard/-/commit/49be15ac7bcae04459d89b0488c09ed7e875f57b.patch