Don't send session committed broadcast for dry runs

For staged installs, pre-reboot verification performs a dry run install.
Since this dry run install is non-staged, the session committed
broadcast will be sent, in some cases causing app icons to
erroneously appear. Add check for this case.

Test: Inspect SESSION_COMMITTED broadcasts sent for a staged install
      with and without this patch
Bug: 139663018

Change-Id: Ib0ba29a4506cda8da1865926ae62b137e1dce8ff