Avoid spamming native_set_position_mode by caching

Bug: 78116022
Change-Id: I1a8522cad8b884cdb6ad21cbd897831cb8bf9372
Fixes: 78116022
Test: m -j ROBOTEST_FILTER=GnssPositionModeTest RunFrameworksServicesRoboTests
Test: Built and manually tested.
3 files changed