[RTT] Fix legacy RTT API

Legacy RTT APIs wrap around the new RTT API. The translation of
results from new to legacy APIs allocated the full number of
results - but only filled-in one of the results - the others
were left null.

Bug: 73884773
Test: RangeApSupporting11McTest:test_legacy_rtt_80211mc_supporting_aps
passes with multiple APs

Change-Id: Id5ec70de272868d92154bdca9eee1d398c3a1801