[Doc] Fix react-query devtools documentation

[dricholm]

Solves #10342

Problem

React-admin v5 uses a new version of TanStack React Query compared to v4. The devtools are not bundled in the package anymore and have to be installed separately. Related documentation was not updated.

Solution

Update the related docs to match with the new changes.

How To Test

Follow the steps and confirm devtools is shown.

Additional Checks

• The PR targets master for a bugfix, or next for a feature
• The PR includes unit tests (if not possible, describe why)
  • No unit tests as it's a doc update.
• The PR includes one or several stories (if not possible, describe why)
  • No stories as it's a doc update.
• The documentation is up to date

[fzaninotto]

Thanks!