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/preact/compat/server.js

@@ -0,0 +1,26 @@
+/* eslint-disable */
+var renderToString;
+try {
+	const mod = require('preact-render-to-string');
+	renderToString = mod.default || mod.renderToString || mod;
+} catch (e) {
+	throw Error(
+		'renderToString() error: missing "preact-render-to-string" dependency.'
+	);
+}
+
+var renderToPipeableStream;
+try {
+	const mod = require('preact-render-to-string/stream-node');
+	renderToPipeableStream = mod.default || mod.renderToPipeableStream || mod;
+} catch (e) {
+	throw Error(
+		'renderToPipeableStream() error: update "preact-render-to-string" dependency to at least 6.5.0.'
+	);
+}
+
+module.exports = {
+	renderToString: renderToString,
+	renderToStaticMarkup: renderToString,
+	renderToPipeableStream: renderToPipeableStream
+};