Use `PushFilePreparer` to push files in OverlayDeviceTests

This change modifies the test config file by switching to use `PushFilePreparer` instead of `FilePusher`, since the `FilePusher` class which is defined in `compatibility-tradefed` is designed for the tests that are part of compatibility suite, but OverlayDeviceTests is not.

Bug: 220991354
Test: atest-src OverlayDeviceTests \
          --experimental-device-driven-test \
          --experimental-java-runtime-dependencies \
          --bazel-arg=--test_timeout=48000
Test: atest OverlayDeviceTests
Change-Id: Ice90776cb2eae43be25190979f1b69a52e97920d