Don't allow opening reference profiles for writing when ART Service is

enabled.

The dexopt code in installd is only used for OTA in that case, and this
should happen then. This is an extra safety check to ensure that.

There are more cases when existing files are potentially opened for
writing, which aren't addressed:

- open_snapshot_profile is used for app and boot image profile
  snapshots. This shouldn't be called at all when ART Service is in
  use, but there's no risk of reading truncated data from them since
  they're only written to.

- open_output_file is only used for a dex2oat swap file, but ART
  Service creates them at different guaranteed unique paths through
  art::artd::NewFile.

- RestorableFile::CreateWritableFile uses a .tmp file suffix that ART
  Service doesn't use.

Test: m dist
      system/update_engine/scripts/update_device.py \
        out/dist/*-ota-eng.*.zip
Bug: 251921228
Change-Id: I1d6f64beaf2bd8c9a05aa5c17a33492b89c903fd