Avoid panics on not owner errors because they should go away

[ajroetker]

No description provided.

[mattayes]

[Q] How do we know these will go away?

[ajroetker]

They are owned by an expired lease

[mattayes]

We should check this earlier, otherwise we're doing unnecessary retries:

	switch {
	case err == nil:
		return false
	// Ignore ErrNotOwner because most likely the previous owner panic'ed or exited badly. 
	// So we'll ignore the error and let the mailbox creator retry later.  We don't want to panic
	// in that case because it will take down more mailboxes and make it worse.
	case errors.Is(err, registry.ErrNotOwner):
		err = nil
		return false
	default:
		return true
	}
})
if err != nil {
	panic(fmt.Errorf("%w: unable to deregister mailbox: %v, error: %v", errDeregisteredFailed, nsName, err))
}

[mattayes]

Same here:

	switch {
	case err == nil:
		return false
	case errors.Is(err, registry.ErrNotOwner):
		err = nil
		return false
	default:
		return true
	}
})
if err != nil {
	panic(fmt.Errorf("%w: unable to deregister mailbox: %v, error: %v", errDeregisteredFailed, nsName, err))
}