[CICD] Upload unittest coverage report to FlagCICD platform && Access FlagCICD runner

[BrianPei]

Description

Simplifies and consolidates the coverage report generation logic in the CI unittest workflow, reducing redundant steps and dependencies.
Need to test uploading reports to FlagCICD step in CI env.

Type of change

• New feature (non-breaking change which adds functionality)
• Infra/Build change (changes to CI/CD workflows or build scripts)
• Code refactoring
• Documentation change
• Bug fix
• Breaking change

Changes

• Merged Generate Coverage Report into the Execute Tests step — coverage combine and json generation now run inline after bash test.sh, following the same pattern as Megatron-LM-FL
• Coverage collection is gated on test_type == 'unittest' to avoid running for lint/debug groups, and pip install is done only once
• Removed fetch-depth: 0 from checkout steps (not required for unit test runs)
• Removed unused/leftover scripts from the repository

TODO

Checklist:

• I have read and followed the contributing guidelines.
• The functionality is complete
• I have commented my code, particularly in coverage report uploading steps
• My changes generate no new warnings
• I have added/updated tests that prove my feature works on Cuda and Metax platform.
• New and existing unit tests pass locally on Cuda and Metax platform.

[Copilot]

Pull request overview

This PR refactors the unit test CI workflow to generate and upload a per-test-group Python coverage JSON report, and removes some leftover/unused CI config lines.

Changes:

• Consolidates coverage setup + coverage JSON generation into the Execute Tests step (gated to test_type == unittest).
• Renames coverage artifacts/reports to include matrix.test_group.name to avoid collisions.
• Cleans up CUDA runner config by removing commented-out container volume entries.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 3 comments.

File	Description
.github/workflows/unit_tests_common.yml	Refactors coverage generation, adjusts artifact naming, and uploads the report to FlagCICD.
.github/configs/cuda.yml	Removes commented-out container volume lines.

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[Darryl233]

LGTM