[R] Fix the version selector dropdown in the dev docs #33555
Description
ARROW-17887 updates the docs to use Bootstrap 5 which will break the docs version dropdown selector, as it relies on replacing a page element, but the page elements are different in this version of Bootstrap.
Reporter: Nicola Crane / @thisisnic
Assignee: Nicola Crane / @thisisnic
PRs and other links:
Note: This issue was originally created as ARROW-18391. Please see the migration documentation for further details.