fix(phpstan): improve cron execution and error handling

Summary of changes:
- Removed redundant PHPDoc from `ExecCrons` class.
- Ensured the input `cronId` is cast to an integer before calling `runCron` in `ExecCrons` class.
- Removed extraneous details from PHPDoc in `Manager` class.
- Added more robust checking for parameters in `Manager` class.
- Included method existence check for `deactivate` before calling it in `QuiqqerCrons` class.

These changes contribute towards improving cron execution and handling potential errors more
gracefully.

Related: #57