Pending requests to use rooms or equipment should block staff (or prompt them with an override) when editing existing bookings to times which would conflict.

Use case: we had a pending request for our playroom for later in the day that staff hadn't yet approved for use because admin staff were in meetings. When a no-show called during the meeting to rebook for later, the staff member didn't know a booking was pending because the system doesn't hold the room, so they rebooked over the pending request. Our pending request had to be denied for lack of availability, instead of giving our staff an opportunity to reschedule the no-show for a time that hadn't already been requested. This led to a very poor patron experience for the patron who never got a chance to use the room in favor of the person who had a chance and missed their reservation but still got to hold the room again.