Updates to dynamic recurring tasks aren't picked up until the scheduler restarts

[cupatea]

When dynamic tasks enabled, only two cases are handled on each poll:

• Creating new recurring task
• Deleting existing recurring task

The third case, when task updated is not handled. If dynamic task's schedule changed, arguments, queue_name, priority, class_name, etc., the running scheduler keeps firing against the pre-update version until the process is restarted.

Example:

task = SolidQueue.schedule_recurring_task(
  "platform-import-schedule-14",
  class: "PlatformlmportJob",
  args: [{ company_id: 14 }],
  schedule: "0 4 * * * Europe/Kyiv" # 04:00 EEST
)

# scheduler picks it up on the next poll

task.update!(schedule: "0 8 * * * Europe/Kyiv") # 08:00 EEST

# expected: jobs start at 08:00 EEST
# actual:   scheduler keeps the original "04:00 EEST" cadence until restart