Pass rollbackId to submitSessionToApexService() (2/n)

Do the plumbing to pass rollbackId from
handlePreRebootVerification_Start() all the way to
submitSessionToApexService().

This allows us to remove mSessionRollbackIds.

Bug: 167996901
Test: atest StagedInstallTest StagedInstallInternalTest
Change-Id: Icc357561a4743683b3aae796ed7723eec66e3a6e