FRE-600: Fix code review blockers

- Consolidated duplicate UndoManagers to single instance
- Fixed connection promise to only resolve on 'connected' status
- Fixed WebSocketProvider import (WebsocketProvider)
- Added proper doc.destroy() cleanup
- Renamed isPresenceInitialized property to avoid conflict

Co-Authored-By: Paperclip <noreply@paperclip.ing>

node_modules/core-js/modules/esnext.reflect.delete-metadata.js

@@ -0,0 +1,22 @@
+'use strict';
+var $ = require('../internals/export');
+var ReflectMetadataModule = require('../internals/reflect-metadata');
+var anObject = require('../internals/an-object');
+
+var toMetadataKey = ReflectMetadataModule.toKey;
+var getOrCreateMetadataMap = ReflectMetadataModule.getMap;
+var store = ReflectMetadataModule.store;
+
+// `Reflect.deleteMetadata` method
+// https://github.com/rbuckton/reflect-metadata
+$({ target: 'Reflect', stat: true }, {
+  deleteMetadata: function deleteMetadata(metadataKey, target /* , targetKey */) {
+    var targetKey = arguments.length < 3 ? undefined : toMetadataKey(arguments[2]);
+    var metadataMap = getOrCreateMetadataMap(anObject(target), targetKey, false);
+    if (metadataMap === undefined || !metadataMap['delete'](metadataKey)) return false;
+    if (metadataMap.size) return true;
+    var targetMetadata = store.get(target);
+    targetMetadata['delete'](targetKey);
+    return !!targetMetadata.size || store['delete'](target);
+  }
+});