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/pngjs/lib/sync-reader.js

@@ -0,0 +1,45 @@
+"use strict";
+
+let SyncReader = (module.exports = function (buffer) {
+  this._buffer = buffer;
+  this._reads = [];
+});
+
+SyncReader.prototype.read = function (length, callback) {
+  this._reads.push({
+    length: Math.abs(length), // if length < 0 then at most this length
+    allowLess: length < 0,
+    func: callback,
+  });
+};
+
+SyncReader.prototype.process = function () {
+  // as long as there is any data and read requests
+  while (this._reads.length > 0 && this._buffer.length) {
+    let read = this._reads[0];
+
+    if (
+      this._buffer.length &&
+      (this._buffer.length >= read.length || read.allowLess)
+    ) {
+      // ok there is any data so that we can satisfy this request
+      this._reads.shift(); // == read
+
+      let buf = this._buffer;
+
+      this._buffer = buf.slice(read.length);
+
+      read.func.call(this, buf.slice(0, read.length));
+    } else {
+      break;
+    }
+  }
+
+  if (this._reads.length > 0) {
+    return new Error("There are some read requests waitng on finished stream");
+  }
+
+  if (this._buffer.length > 0) {
+    return new Error("unrecognised content at end of stream");
+  }
+};