search for dbt_core source distribution

[MichelleArk]

resolves #N/A

Problem

setuptools released a patch that enforcing a naming standard on source distributions to use '_' instead of '-'. this breaks our regex-based search in CI: https://github.com/dbt-labs/dbt-core/actions/runs/8665429967/job/23764102566?pr=9891

https://setuptools.pypa.io/en/stable/history.html

pypa/setuptools#4300

Solution

update regex to search using _ also updating to only search for dbt_core explicitly since we no longer build other distributions in this step.

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/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 88.08%. Comparing base (3c4456d) to head (ef512ae).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #9915      +/-   ##
==========================================
- Coverage   88.09%   88.08%   -0.02%     
==========================================
  Files         178      178              
  Lines       22459    22459              
==========================================
- Hits        19786    19782       -4     
- Misses       2673     2677       +4     

Flag	Coverage Δ
integration	85.44% <ø> (-0.02%)	⬇️
unit	61.82% <ø> (ø)

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[mikealfare]

I assume this is only run on main?