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/.eslintrc.json

@@ -0,0 +1,19 @@
+{
+  "parserOptions": { "ecmaVersion": 2018 },
+  "extends": ["eslint:recommended", "prettier"],
+  "env": {
+    "node": true,
+    "es6": true
+  },
+  "rules": {
+    "no-var": "error"
+  },
+  "overrides": [
+    {
+      "files": ["test/*.js", "examples/*.js"],
+      "rules": {
+        "no-console": "off"
+      }
+    }
+  ]
+}