[terraform] Remove references to legacy services

Summary:
This fixes the no-op plan difference on staging.
Part of ENG-4543. ECS-based services work well for so long so we can remove the legacy ones.

Test Plan:

• terraform plan on staging now shows no changes
• terraform plan on prod removes the legacy services and results in state being identical as staging

Reviewers: varun, michal, jon

Reviewed By: michal

Subscribers: ashoat, tomek

Differential Revision: https://phab.comm.dev/D9177