trusty: local host package search only for local images

Do not search for local host package by default, this
breaks invoking the Trusty avd from ATP.

Bug: 401710433
Test: acloud-dev create --avd-type trusty \
      --branch=git_main-throttled-nightly \
      --build-target=qemu_trusty_arm64-trunk_staging-userdebug
Change-Id: Id96567a8cfee56acdf9fb8146f048197e8ce4402