chore: Update validate-pr workflow (#20072)

Update validate-pr action to getsentry/github-workflows@71588dd.

Changes included:
- Skip all checks when a maintainer reopens a PR
(getsentry/github-workflows#161)
- Skip checks for users with write access
(getsentry/github-workflows#162)

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: stephanie-anderson

.github/workflows/validate-pr.yml

@@ -10,7 +10,7 @@ jobs:
     permissions:
       pull-requests: write
     steps:
-      - uses: getsentry/github-workflows/validate-pr@0b52fc6a867b744dcbdf5d25c18bc8d1c95710e1
+      - uses: getsentry/github-workflows/validate-pr@71588ddf95134f804e82c5970a8098588e2eaecd
         with:
           app-id: ${{ vars.SDK_MAINTAINER_BOT_APP_ID }}
           private-key: ${{ secrets.SDK_MAINTAINER_BOT_PRIVATE_KEY }}