Update GitHub Actions to latest major versions (#36964)

Update all Actions to their latest major versions:

- `actions/checkout`: v5 → v6
- `dorny/paths-filter`: v3 → v4
- `pnpm/action-setup`: v4 → v5
- `docker/setup-qemu-action`: v3 → v4
- `docker/setup-buildx-action`: v3 → v4
- `docker/build-push-action`: v6 → v7
- `docker/metadata-action`: v5 → v6
- `docker/login-action`: v3 → v4
- `crazy-max/ghaction-import-gpg`: v6 → v7
- `aws-actions/configure-aws-credentials`: v5 → v6

All updates are Node 24 runtime bumps with no workflow-breaking changes
for our usage.

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

.github/workflows/pull-e2e-tests.yml

@@ -25,7 +25,7 @@ jobs:
         with:
           go-version-file: go.mod
           check-latest: true
-      - uses: pnpm/action-setup@v4
+      - uses: pnpm/action-setup@v5
       - uses: actions/setup-node@v6
         with:
           node-version: 24