fix target file for dbt-common CI

[emmyoop]

Problem

dbt-common CI runs tests with dbt-core. We need to update the ref to be the one we want to test against. The file we were updating no longer exists due to hatch implementation.

Solution

Use core/hatch.toml

Checklist

• I have read the contributing guide and understand what's expected of me.
• I have run this code in development, and it appears to resolve the stated issue.
• This PR includes tests, or tests are not required or relevant for this PR.
• This PR has no interface changes (e.g., macros, CLI, logs, JSON artifacts, config files, adapter interface, etc.) or this PR has already received feedback and approval from Product or DX.
• This PR includes type annotations for new and modified functions.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 92.01%. Comparing base (97df927) to head (a3919bc).
⚠️ Report is 2 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #12258      +/-   ##
==========================================
- Coverage   92.01%   92.01%   -0.01%     
==========================================
  Files         203      203              
  Lines       24972    24972              
==========================================
- Hits        22979    22978       -1     
- Misses       1993     1994       +1     

Flag	Coverage Δ
integration	88.96% <ø> (+0.05%)	⬆️
unit	65.32% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

Components	Coverage Δ
Unit Tests	65.32% <ø> (ø)
Integration Tests	88.96% <ø> (+0.05%)	⬆️

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.