Fall back to Read Request when reading Characteristic Extended Properties

If Read Multiple Request is not supported, fall back to Read Request.

Test: Manually tested against device modified to not support Read
Multiple Request (GATT_REQ_READ_MULTI in gatt_server_handle_client_req
forced to return GATT_REQ_NOT_SUPPORTED)
Bug: 110864501

Change-Id: I262678c93f2c3e56832502d1f46542dfc97c7904