[pm] Fix appId naming

+ appId should not be called userId (at least in dumpsys)
+ fixing a mistake from ag/16740473 (line 1285)
+ remove log spam when appId was not set for package settings with
  shared user setting which is expected during initialization (line 1286)

BUG: 235381248
Test: builds / dumpsys
Test: will test with manual OTA
Change-Id: I9ca72c151107bf4c72f0728065fe6b7447049483