Some small fixes in SBOM generation

1) Fix column name typo in compliance metadata db
2) Add new identifier type: Piper
3) Add checking in case some static libraries' soong module could not be identified, which happens on some java static libraries

Test: presubmits
Test: build/soong/tests/sbom_test.sh
Change-Id: I2815ddff5f39b5a562668ac19f694461f8a01cd7