Delete stale-pr.yml

Removing as this isn't used.

.github/workflows/stale-pr.yml

-name: Mark PR As Stale
-on:
-  schedule:
-    - cron: "30 1 * * *"
-jobs:
-  close-issues:
-    runs-on: ubuntu-latest
-    permissions:
-      issues: write
-      pull-requests: write
-    steps:
-      - uses: actions/stale@v7
-        with:
-          stale-issue-label: "stale"
-          stale-pr-label: "stale"
-          stale-pr-message: "🚧🚨 This Pull Request is being marked as stale due to 30 days of inactivity. 🚧🚨"
-          days-before-pr-stale: 30
-          days-before-pr-close: -1
-          repo-token: ${{ secrets.GITHUB_TOKEN }}