[pm] skip required verifier if it's disabled

No point in waiting for the timeout if we know it's disabled.

Added warning message:
08-03 18:11:01.172  1713  1992 W PackageManager: Required verifier: com.android.vending is disabled

BUG: 238174982
Test: manual with `adb shell pm disable com.android.vending`
Change-Id: I8ecbdebeb16b444d18f5204cc99f6056c09646af