Simple cron log should not log non scheduled jobs.

Problem/Motivation

When cron logging is enable, each time cron is executed, simple_cron create a warn log "Cron job @job should not be running." for each job that is not executed at this time.

This is not an error even not an info, it's perfectly normal that a job is not executed outside its scheduled time.

It pollutes the logs, specially if cron is run frequently and with a lot of jobs.

Steps to reproduce

• Enable cron logging
• Be sure that at least several cron jobs are scheduled
• Wait to a cron execution
• Parse log, there should be a warning per task that is not executed that says "Cron job @job should not be running."

Proposed resolution

Remove the warning in web/modules/contrib/simple_cron/src/Entity/CronJob.php:312:

      if (!$plugin ) {
        $this->logger->warning('Cron job @job could not be run: missing plugin.', ['@job' => $this->label()]);
        return FALSE;
      }
      if (!$this->shouldRun($request_time, $force)) {
        return FALSE;
      }