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/simple-concat/index.js

@@ -0,0 +1,15 @@
+/*! simple-concat. MIT License. Feross Aboukhadijeh <https://feross.org/opensource> */
+module.exports = function (stream, cb) {
+  var chunks = []
+  stream.on('data', function (chunk) {
+    chunks.push(chunk)
+  })
+  stream.once('end', function () {
+    if (cb) cb(null, Buffer.concat(chunks))
+    cb = null
+  })
+  stream.once('error', function (err) {
+    if (cb) cb(err)
+    cb = null
+  })
+}