Flatten the workflow hierarchy for run_unit_tests

[dixonjoel]

What does this Pull Request accomplish?

Eliminate one layer of workflow (run_unit_tests.yml) and put a call to run_and_upload_unit_tests composite action directly from test_package.yml.

Why should this Pull Request be merged?

We were getting four levels of workflow hierachy running unit tests. This is kind of unnecessary and hard to follow the flow of the CI.

What testing has been done?

Current PR checks and unit tests still run and pass.

[Copilot]

Pull Request Overview

This PR flattens the GitHub Actions workflow hierarchy by eliminating the run_unit_tests.yml workflow file and directly integrating its functionality into test_package.yml. This reduces the workflow call chain from four levels to three levels, making the CI flow easier to follow.

Key changes:

• Removed intermediate run_unit_tests.yml workflow call
• Added direct job steps for checkout, Python setup, and Poetry configuration
• Integrated the run_and_upload_unit_tests composite action call directly

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[github-actions]

Test Results

  120 files  ±0    120 suites  ±0   3m 15s ⏱️ -10s
  240 tests ±0    238 ✅ ±0   2 💤 ±0  0 ❌ ±0 
2 400 runs  ±0  2 370 ✅ ±0  30 💤 ±0  0 ❌ ±0 

Results for commit 03c59bb. ± Comparison against base commit ca86811.