revert(api): decouple api from curriculum

This reverts commit c077ffe4b9
via PR #40703

api-server/common/utils/empty-protector.js

@@ -0,0 +1,13 @@
+const emptyProtector = {
+  blocks: [],
+  challenges: []
+};
+// protect against malformed map data
+// protect(block: { challenges: [], block: [] }|Void) => block|emptyProtector
+export default function protect(block) {
+  // if no block or block has no challenges or blocks
+  if (!block || !(block.challenges || block.blocks)) {
+    return emptyProtector;
+  }
+  return block;
+}