Reapply "snapshotctl: Add apply-update option"

This reverts commit 1af72609318a8776c51d9094d63b4325e243f62d.

Fix: Allow BootControlClient.h to be used in -user builds

Bug: 319309466
Test: Build on -user branch
Change-Id: I93e95e35b29a98816b2f33fe9fa6859655934cd5
1 file changed