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/is-html/readme.md

@@ -0,0 +1,31 @@
+# is-html [![Build Status](https://travis-ci.org/sindresorhus/is-html.svg?branch=master)](https://travis-ci.org/sindresorhus/is-html)
+
+> Check if a string is HTML
+
+
+## Install
+
+```
+$ npm install is-html
+```
+
+
+## Usage
+
+```js
+const isHtml = require('is-html');
+
+isHtml('<p>I am HTML</p>');
+//=> true
+
+isHtml('<!doctype><html><body><h1>I ❤ unicorns</h1></body></html>');
+//=> true
+
+isHtml('<cake>I am XML</cake>');
+//=> false
+
+isHtml('>+++++++>++++++++++>+++>+<<<<-');
+//=> false
+```
+
+Note: It does not detect deprecated HTML tags.