Floss: Prevent propagating SDP failure message during RNR

aosp/2529445 sends a new tBTA_DM_SEARCH on completing RNR, but it is
interpreted as a failed SDP request on btif_dm.cc, because it is
populated with zero num_uuids.
As a side effect, the handler tries to populate some value into the
UUIDs property, and that causes an extraneous call to invoke remote
device property change callback, which breaks Floss.

This CL treats zero num_uuids as a non-failure case.

Bug: 285098711
Test: Verify no "SDP failed" message when pairing a new device

Change-Id: If5d6dfa3290fb3cd6d97588338b31c20154ebf12