passpoint-r2: define getMatchingOsuProviders(List<ScanResult>) API

This API is required to support control of OSU Service Providers with
scan results on Setting UI.
Internally, previous API is merged into new API to take a list of
ScanResult Objects instead of a single ScanResult.

Bug: 119514793
Test: ./frameworks/base/wifi/tests/runtests.sh
Change-Id: Ib2f2e406c8c295c83924e7884657b4088dd23bb3
Signed-off-by: Ecco Park <eccopark@google.com>