Restrict purging of recurring jobs to bundle-managed schedule

[paroe]

This PR addresses excessive re-scheduling in the JobRecurringScheduleListener.

Currently, there are two issues in my opinion:

1. The listener purges all schedules, including those from Symfony's native Scheduler bundle.
   This means that if you have other tasks defined with the #[AsCronTask(...)] attribute, all but the first one are purged and will no longer be executed.
   The first one still runs, but only because of the $key === 0 check.

2. The schedule is recalculated whenever any recurring job is executed, rather than only when the heartbeat is received.
   With many recurring jobs, this leads to unnecessary load.

[Matys333]

Thanks @paroe, much appreciated, this slipped past me.