shared/gatt-client: Fix not freeing notify data
shared/gatt-client: Fix not freeing notify data

notify_data_write_ccc takes another reference in case it succeed so
the original reference should be dropped to cause the data to be freed
once notify_data_write_ccc completes.

pkarasev3/bluez,pkarasev3/bluez,pkarasev3/bluez,pkarasev3/bluez