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/core-js/modules/es.date.set-year.js

@@ -0,0 +1,20 @@
+'use strict';
+var $ = require('../internals/export');
+var uncurryThis = require('../internals/function-uncurry-this');
+var toIntegerOrInfinity = require('../internals/to-integer-or-infinity');
+
+var DatePrototype = Date.prototype;
+var thisTimeValue = uncurryThis(DatePrototype.getTime);
+var setFullYear = uncurryThis(DatePrototype.setFullYear);
+
+// `Date.prototype.setYear` method
+// https://tc39.es/ecma262/#sec-date.prototype.setyear
+$({ target: 'Date', proto: true }, {
+  setYear: function setYear(year) {
+    // validate
+    thisTimeValue(this);
+    var yi = toIntegerOrInfinity(year);
+    var yyyy = yi >= 0 && yi <= 99 ? yi + 1900 : yi;
+    return setFullYear(this, yyyy);
+  }
+});