Set system.set_reboot_required_witnessed to use /tmp/salt

[tqre]

Fixes #58125

Removed the depends-decorator as it was not functioning correctly. The file was touched always in the NILinuxRT -specific directory. Made a simple check for the os_family instead. Also added clarification on module functionality on setting the reboot flag. Renamed the file created to be more precise on it's meaning.

Commits signed with GPG?

No

[tqre]

Found a typo and removed the unused import. However, I'm not sure what is the correct string formatting here, I changed it according to https://docs.saltstack.com/en/latest/topics/development/conventions/style.html#formatting-strings

[sagetherage]

Since this doesn't have a test case, dropping it from the scope for the Magnesium release.

[mdschmitt]

Is there anything that can be done to un-block this?

[Ch3LL]

This PR requires a test case, a changelog file and looks like previously pre-commit was failing.

[Ch3LL]

Anyone willing to push this one to completion?

[Ch3LL]

Closing due to inactivity. Please let me know if you want me to re-open this PR or open a new PR against the master branch including the feedback in the PR