arrow

MINOR: [Dev] Fix handling minor issues on Dev PR worflow (#44987)

### Rationale for this change

This is a follow up from: https://github.com/apache/arrow/pull/44975#issuecomment-2529683575

### What changes are included in this PR?

Fix the issue_check workflow to not assume all PRs are going to have an associated issue. Fix the worflow for minor issues.

### Are these changes tested?

I've tested on my fork.

### Are there any user-facing changes?
No

Authored-by: Raúl Cumplido <raulcumplido@gmail.com>
Signed-off-by: Sutou Kouhei <kou@clear-code.com>