Revert "CI: use namespace.so" (#31060)

.github/workflows/compile-openpilot/action.yaml

@@ -1,5 +1,11 @@
 name: 'compile openpilot'
 
+inputs:
+  cache_key_prefix:
+    description: 'Prefix for caching key'
+    required: false
+    default: 'scons'
+
 runs:
   using: "composite"
   steps:
@@ -18,4 +24,4 @@ runs:
       if: github.ref == 'refs/heads/master'
       with:
         path: .ci_cache/scons_cache
-        key: scons-${{ runner.arch }}-${{ env.CACHE_COMMIT_DATE }}-${{ github.sha }}
+        key: ${{ inputs.cache_key_prefix }}-${{ env.CACHE_COMMIT_DATE }}-${{ github.sha }}