Enable adservice override for deployment

[adinauer]

Vanilla service (prebuilt docker image) is still used after adding Sentry to this demo. This should change it.

Changes

Please provide a brief description of the changes here.

Merge Requirements

For new features contributions please make sure you have completed the following
essential items:

• CHANGELOG.md updated to document new feature additions
• Appropriate documentation updates in the docs folder

Maintainers will not merge until the above have been completed. If you're unsure
which docs need to be changed ping the
@open-telemetry/demo-approvers.