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-wsl/index.d.ts

@@ -0,0 +1,15 @@
+/**
+Check if the process is running inside [Windows Subsystem for Linux](https://msdn.microsoft.com/commandline/wsl/about) (Bash on Windows).
+
+@example
+```
+import isWsl = require('is-wsl');
+
+// When running inside Windows Subsystem for Linux
+console.log(isWsl);
+//=> true
+```
+*/
+declare const isWsl: boolean;
+
+export = isWsl;