Add "workingHours" object to API queries of bookingServices to expose custom availability
Booking Services can be configured with custom availability, through the MS OEM Bookings configuration portal. However this availability is not exposed to the 1.0 or beta Graph API.
My suggestion is to model the workingHours object from List staffMembers Graph API query. Just as custom availability is exposed for staff, it shoudl be exposed for services.
This is important - we need to be able to report on how many working slots are available when using custom hours.