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/lodash/stubString.js

@@ -0,0 +1,18 @@
+/**
+ * This method returns an empty string.
+ *
+ * @static
+ * @memberOf _
+ * @since 4.13.0
+ * @category Util
+ * @returns {string} Returns the empty string.
+ * @example
+ *
+ * _.times(2, _.stubString);
+ * // => ['', '']
+ */
+function stubString() {
+  return '';
+}
+
+module.exports = stubString;