Add Set(iterable) polyfill for IE11

packages/node_modules/@node-red/editor-client/src/js/polyfills.js

@@ -37,5 +37,20 @@
             }
             return result;
         }
+
+        if (new Set([0]).size === 0) {
+            // IE does not support passing an iterable to Set constructor
+            var _Set = Set;
+            Set = function Set(iterable) {
+                var set = new _Set();
+                if (iterable) {
+                    iterable.forEach(set.add, set);
+                }
+                return set;
+            };
+            Set.prototype = _Set.prototype;
+            Set.prototype.constructor = Set;
+        }
+
     }
 })();