[8.x] Fix schedule:work command Artisan binary name

[kekalainen]

Currently the schedule:work command assumes the Artisan binary is called artisan and fails to execute the schedule:run command if that's not the case.

root@a529d380561a:/var/www/html# php cli schedule:work
Schedule worker started successfully.

[2022-04-21T16:35:00+00:00] Execution #1 output:
Could not open input file: artisan

This PR addresses the issue by utilizing the ARTISAN_BINARY constant.