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/path-exists/index.d.ts

@@ -0,0 +1,28 @@
+declare const pathExists: {
+	/**
+	Check if a path exists.
+
+	@returns Whether the path exists.
+
+	@example
+	```
+	// foo.ts
+	import pathExists = require('path-exists');
+
+	(async () => {
+		console.log(await pathExists('foo.ts'));
+		//=> true
+	})();
+	```
+	*/
+	(path: string): Promise<boolean>;
+
+	/**
+	Synchronously check if a path exists.
+
+	@returns Whether the path exists.
+	*/
+	sync(path: string): boolean;
+};
+
+export = pathExists;