[RTT] Fix legacy API crash on invalid RTT results

Legacy RTT API permitted access of results (e.g. distance) even
when the measurement failed - the new API throws an exception.

Add checks to the translation code (from new to legacy) so that
exceptions aren't thrown - results are simply 0.

Bug: 73297815
Test: builds, integration test is being developed
Change-Id: I8286e36afe5597cc372e65b75f03a382ca0cd2b3