Changes

feat(tidb/ghpr_check2): disable artifactVerify for feature branches (#3958)

When the base branch is a feature branch (starts with "feature/"), set
artifactVerify to false for tikv and pd artifact downloads. This
prevents verification failures when artifacts may not be available for
feature branches.

Changes:
- Add feature branch detection using regex pattern matching
- Conditionally set artifactVerify based on branch type
- Apply to both tikv and pd artifact fetches
 (commit: 274fc96)