STS add Mainline test skips Bug: 238805898 Test: sts-tradefed run sts-dynamic-develop --test-arg com.android.tradefed.testtype.AndroidJUnitTest:instrumentation-arg:sts-should-skip-mainline:=true --build-attribute "sts-should-skip-mainline=true" Change-Id: I5d78cee2f4bbc3a66cbcf31fb6151910147bc7be