lock streamdeck_ui.lock is never released/deleted

[zen2]

Describe the bug
Once streamdeck-ui have exited properly by using "exit" in interface or sending signal SIGTERM to terminate the process you still can find the lock file streamdeck_ui.lock (/tmp/streamdeck_ui.lock on my system).

To Reproduce
Steps to reproduce the behavior:

1. Launch streamdeck-ui
2. Exit streamdeck-ui
3. ls -l /tmp/streamdeck_ui.lock

Expected behavior
Lock file shouldn't exist any more once streamdeck-ui have terminated.

Operating system (please complete the following information)

• OS: Gentoo Linux
• Desktop environment: openbox
• Python version: 3.11
• streamdeckui version: 2.0.15

Stream Deck Version

• stream deck XL

[cstromblad]

I have created a pull request to fix this bug. #378