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/level-js/util/support.js

@@ -0,0 +1,17 @@
+'use strict'
+
+var Buffer = require('buffer').Buffer
+
+exports.test = function (key) {
+  return function test (impl) {
+    try {
+      impl.cmp(key, 0)
+      return true
+    } catch (err) {
+      return false
+    }
+  }
+}
+
+// Detect binary key support (IndexedDB Second Edition)
+exports.bufferKeys = exports.test(Buffer.alloc(0))