chore: bump graalvm/setup-graalvm from 1.6.3 to 1.6.4 (#2608)

Bumps graalvm/setup-graalvm from 1.6.3 to 1.6.4. Reviewed and approved by @phipag. Review performed by Claude: pinned SHAs verified against upstream tags, upstream action.yml unchanged so no input changes, only runtime dependency change is @actions/cache, CI green including graalvm-build.

Author: dependabot[bot]

.github/workflows/check-build.yml

@@ -107,7 +107,7 @@ jobs:
             powertools-*/**
             pom.xml
       - name: Setup GraalVM
-        uses: graalvm/setup-graalvm@0def53c0fd8534bc13416c9469f5be45265824fd # v1.6.3
+        uses: graalvm/setup-graalvm@5298d94fb55a4f185c602eeac5de1b553882abe2 # v1.6.4
         with:
           # Pinned to 21.0.8 due to unsafeAllocated enforcement in 21.0.10+. See #2416
           java-version: "21.0.8"