docs: update with-one-login-per-subdomain example to use multitenancy

[porcellus]

Summary of change

update with-one-login-per-subdomain example to use multitenancy

Related issues

• Link to issue1 here
• Link to issue1 here

Test Plan

(Write your test plan here. If you changed any code, please provide us with clear instructions on how you verified your changes work. Bonus points for screenshots and videos!)

Documentation changes

(If relevant, please create a PR in our docs repo, or create a checklist here highlighting the necessary changes)

Checklist for important updates

• [ ] Changelog has been updated
• [ ] frontendDriverInterfaceSupported.json file has been updated (if needed)
• [ ] Changes to the version if needed
  • In package.json
  • In package-lock.json
  • In lib/ts/version.ts
• [ ] Had run npm run build-pretty
• [ ] Had installed and ran the pre-commit hook
• [ ] 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.
• [ ] If added a new recipe interface, then make sure that the implementation of it uses NON arrow functions only (like someFunc: function () {..}).
• [ ] If I added a new recipe, I also added the recipe entry point into the size-limit section of package.json with the size limit set to the current size rounded up.
• [ ] If I added a new recipe, I also added the recipe entry point into the rollup.config.mjs

Remaining TODOs for this PR

• [ ] Item1
• [ ] Item2

[github-actions[bot]]

size-limit report 📦

Path	Size
lib/build/index.js	10.98 KB (0%)
recipe/session/index.js	11.48 KB (0%)
recipe/session/prebuiltui.js	15.59 KB (0%)
recipe/thirdpartyemailpassword/index.js	29.44 KB (0%)
recipe/thirdparty/index.js	26.26 KB (0%)
recipe/emailpassword/index.js	10 KB (0%)
recipe/emailverification/index.js	7.35 KB (0%)
recipe/passwordless/index.js	63.55 KB (0%)
recipe/thirdpartypasswordless/index.js	84.04 KB (0%)
recipe/emailverification/prebuiltui.js	21.67 KB (0%)
recipe/thirdpartyemailpassword/prebuiltui.js	52.52 KB (0%)
recipe/thirdparty/prebuiltui.js	35.77 KB (0%)
recipe/emailpassword/prebuiltui.js	26.47 KB (0%)
recipe/passwordless/prebuiltui.js	100.67 KB (0%)
recipe/thirdpartypasswordless/prebuiltui.js	127.92 KB (0%)
recipe/multitenancy/index.js	5.96 KB (0%)