NetworkScoreManager: Expose SCORE_FILTER_* consts

Rename CACHE_FILTER_* constants to SCORE_FILTER_*
and expose them as @SystemApi so they can be used
by the Wifi module.

Bug: 135998869
Test: compiles
Change-Id: I9eab2e84d0b00fada7629a104566c1099f8b1288
Merged-In: I9eab2e84d0b00fada7629a104566c1099f8b1288