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/scheduler.js

@@ -0,0 +1,15 @@
+// see scheduler.mjs
+
+function unstable_runWithPriority(priority, callback) {
+	return callback();
+}
+
+module.exports = {
+	unstable_ImmediatePriority: 1,
+	unstable_UserBlockingPriority: 2,
+	unstable_NormalPriority: 3,
+	unstable_LowPriority: 4,
+	unstable_IdlePriority: 5,
+	unstable_runWithPriority,
+	unstable_now: performance.now.bind(performance)
+};