Update immutable from 4.0.0-rc.12 to ^4.3.8

- Update immutable dependency to stable v4.3.8
- Add type assertions for getIn calls that now return unknown in v4 stable
- Add skipLibCheck to tsconfig.json for @nteract and @octokit .d.ts compat
- Add patch-package patch for @nteract/commutable .ts source files

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

package.json

@@ -75,7 +75,7 @@
     "i18next-resources-to-backend": "1.2.1",
     "iframe-resizer-react": "1.1.0",
     "immer": "9.0.6",
-    "immutable": "4.0.0-rc.12",
+    "immutable": "^4.3.8",
     "is-ci": "2.0.0",
     "jquery": "3.7.1",
     "jquery-typeahead": "2.11.1",