chore: Adds tests for passing custom cookie and window handler

Summary of change

Adds tests for using custom cookie and window handlers when initialising SuperTokens.

All existing test cases pass

None needed

[ ] Changelog has been updated
[ ] ~~frontendDriverInterfaceSupported.json file has been updated (if needed)~~
- ~~Along with the associated array in lib/ts/version.ts~~
[ ] ~~Changes to the version if needed~~
- ~~In package.json~~
- ~~In package-lock.json~~
- ~~In lib/ts/version.ts~~
[x] Had run npm run build-pretty
[x] Had installed and ran the pre-commit hook
[x] Issue this PR against the latest non released version branch.
- To know which one it is, run find the latest released tag (git tag) in the format vX.Y.Z, and then find the latest branch (git branch --all) whose X.Y is greater than the latest released tag.
- If no such branch exists, then create one from the latest released branch.