fix(deps): revert React 18 upgrade back to React 16

not all of our deps are compatible with React 18 and so this caused many warnings (during install and in the browser console) as well as some bugs (https://github.com/argoproj/argo-workflows/pull/13593)
- those need more updates, primarily breaking changes within argo-ui or decoupling the dependency on argo-ui
- see also https://github.com/argoproj/argo-ui/pull/481#issuecomment-1879775815 with regard to react-router in argo-ui, although that's not the only dep relying on old React in argo-ui (react-form, react-autocomplete, and some of the components are too IIRC)
the main purpose of the upgrade was to be able to upgrade swagger-ui-react, which had an alternate React 16 compatible path and has now been removed from the UI codebase entirely as of #13818
- so the upgrade is no longer necessary for that purpose

Significantly less warnings during yarn install, only the expected ones from transitive deps or incorrect peerDeps of deps per https://github.com/argoproj/argo-workflows/issues/13410#issuecomment-2257365014
Manually tested UI with make start UI=true, functions fine with a few actions.
1. Significantly less warnings in the browser console, only one expected one from transitive deps
yarn build and yarn lint pass.

argoproj / argo-workflows