Log dependency installer fields in installation atom

Add support for the following metric values:
* Whether depencdency installer is enabled for the current session.
* How many missing dependencies there were before the dependency
  installer service was called.

Additionally, log metrics whenever the dependency installer fails to
fetch metrics for whatever reason.

Bug: 372861843
Test: Manual steps - run statsd as below and then run
PackageManagerShellCommandInstallTest and observe output
Test: m statsd_testdrive && statsd_testdrive -e 524
Flag: android.content.pm.sdk_dependency_installer

Change-Id: I6dc0f75b8b957c3552578ab90f1f41f221a6954c