[Cherry-Pick][CI] Add check trigger and logic(#5191)

[EmmonsCurse]

Motivation

Cherry-Pick from #5191

Add a new CI check to validate Cherry-Pick PRs targeting release branches.
This ensures that the PR title contains [Cherry-Pick] and references the original develop PR number, and enforces required FastDeploy RD approvals when the title is invalid.

Modifications

• Added logic in check_approval.sh to fetch PR title and body.
• Validates that release branch PR titles start with [Cherry-Pick] and include the develop PR number (e.g., [CI] Add Cherry-Pick PR check logic #5191).
• If the title is invalid, requires approvals from FastDeploy RDs: qingqing01(dangqingqing) and Jiang-Jia-Jun(jiangjiajun).
• Refactored echo messages to provide a single clear instruction when the check fails.

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!

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
⚠️ Please upload report for BASE (release/online/20251131@a11d17c). Learn more about missing BASE report.

Additional details and impacted files

@@                    Coverage Diff                     @@
##             release/online/20251131    #5227   +/-   ##
==========================================================
  Coverage                           ?   59.11%           
==========================================================
  Files                              ?      317           
  Lines                              ?    38688           
  Branches                           ?     5815           
==========================================================
  Hits                               ?    22871           
  Misses                             ?    13992           
  Partials                           ?     1825           

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