[res] Minor optimizations in OverlayManagerService

- OverlayPaths builder can initialize from another Builder

- Don't loop over all target packages for logging if there's
  nothing to log

Bug: 282215580
Test: build + boot + presubmits
Change-Id: I8545c938d27d1bb740f11c3d6342bf0bdd7b4024
2 files changed