Cancel a pending job without sending texts

There's no way to cancel a job that's in Pending. The pending job card only shows Delay and Schedule, and Cancel only appears once a job is scheduled.

Use case: a customer reschedules, the job goes back to Pending, and then they decide they don't want the service. To cancel it now, you have to mute the customer, schedule the job, cancel it, then unmute them. That's the only way to keep the booking and cancellation texts from going out.

Request: add a Cancel option on pending jobs (the card and the job page) that doesn't send the customer any messages.

Reported by Nick Lesch (Sozo Cleaning) in support conversation #2285. Related: "Scheduler Feature doesnt work great" also mentions not being able to delete pending jobs.

Tracked in Linear: DEV-1621