fix: make ai_task.id change backwards compatible

[DanielleMaywood]

Update the create logic to warn instead of error when no CODER_TASK_ID is set so that we are backwards compatible.

[johnstcn]

Can we also add an integration test that validates backward compat?

[DanielleMaywood]

Can we also add an integration test that validates backward compat?

Can do 👍

[DanielleMaywood]

So the integration test is kinda messy since we have a chicken-and-the-egg problem of coder/coder not yet supporting the updated resource 😄

[johnstcn]

This is fine for now. Once we add support in coder/coder proper then we can update the test.