Revert "Unifying various model update callbacks into one"

Revert submission 31445615-model-callbacks

Reason for revert: <Droidmonitor crested revert due to b/393222548. Will be verified through ABTD for stanadard investigation.>

Reverted changes: /q/submissionid:31445615-model-callbacks

Change-Id: If6893a125756e5abfbb215af377576429bb1c91b
19 files changed