[Cherry-Pick][CI] Sync develop fix and optimizations to 2.4(#6975)

[EmmonsCurse]

Cherry-pick of #6975 #6958 #6939 #7064 to release/2.4.

devPR:#6975 #6958 #6939 #7064

Motivation

• Introduce a unified mechanism to skip unnecessary CI workflows
• Reduce resource usage and avoid running redundant jobs
• Upgrade GitHub Actions to ensure compatibility with the upcoming default switch of GitHub Actions runners to Node 24, while also aligning with the latest major versions of several commonly used actions.

Modifications

• Refine check-bypass workflow to determine whether CI can be skipped

• Integrate skip logic into related workflows based on bypass results

• Upgrade GitHub Actions versions:

  • actions/checkout: v4 → v6
  • actions/setup-python: v5 → v6
  • actions/github-script: v7 → v8
  • codecov/codecov-action: v4 → v6

• Remove legacy extraheader cleanup logic in the clone step, which is no longer required after upgrading actions/checkout.

Usage or Command

N/A

Accuracy Tests

N/A

Checklist

• Add at least a tag in the PR title.
  • Tag list: [[FDConfig],[APIServer],[Engine], [Scheduler], [PD Disaggregation], [Executor], [Graph Optimization], [Speculative Decoding], [RL], [Models], [Quantization], [Loader], [OP], [KVCache], [DataProcessor], [BugFix], [Docs], [CI], [Optimization], [Feature], [Benchmark], [Others], [XPU], [HPU], [GCU], [DCU], [Iluvatar], [Metax]]
  • You can add new tags based on the PR content, but the semantics must be clear.
• Format your code, run pre-commit before commit.
• Add unit tests. Please write the reason in this PR if no unit tests.
• Provide accuracy results.
• If the current PR is submitting to the release branch, make sure the PR has been submitted to the develop branch, then cherry-pick it to the release branch with the [Cherry-Pick] PR tag.

[paddle-bot]

Thanks for your contribution!

[EmmonsCurse]

/skip-ci gpu_4cards_test
/skip-ci pre_ce_test
/skip-ci logprob_test
/skip-ci coverage
/skip-ci base_test