Make module types explicit and convert some to ESM (#15964)

build-scripts/rollup-plugins/dont-hash-plugin.cjs

@@ -0,0 +1,14 @@
+module.exports = function (opts = {}) {
+  const dontHash = opts.dontHash || new Set();
+
+  return {
+    name: "dont-hash",
+    renderChunk(_code, chunk, _options) {
+      if (!chunk.isEntry || !dontHash.has(chunk.name)) {
+        return null;
+      }
+      chunk.fileName = `${chunk.name}.js`;
+      return null;
+    },
+  };
+};