ci: cache embedded postgres downloaded binaries (#18477)

Updates CI job definitions to cache downloaded binaries for embedded-postgres.

.github/actions/embedded-pg-cache/upload/action.yml

@@ -0,0 +1,18 @@
+name: "Upload Embedded Postgres Cache"
+description: Uploads the embedded Postgres cache. This only runs on the main branch.
+inputs:
+  cache-key:
+    description: "Cache key"
+    required: true
+  cache-path:
+    description: "Path to the cache directory"
+    required: true
+runs:
+  using: "composite"
+  steps:
+    - name: Upload Embedded Postgres cache
+      if: ${{ github.ref == 'refs/heads/main' }}
+      uses: actions/cache/save@5a3ec84eff668545956fd18022155c47e93e2684 # v4.2.3
+      with:
+        path: ${{ inputs.cache-path }}
+        key: ${{ inputs.cache-key }}