Merge branch 'mtimoustafa/cdot-7496-stateful-idempontency-key' into 'master'

Preserve idempotency key for purchase pages' form states

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/134813



Merged-by: Vitaly Slobodin <vslobodin@gitlab.com>
Approved-by: Vitaly Slobodin <vslobodin@gitlab.com>
Reviewed-by: Diana Zubova <dzubova@gitlab.com>
Co-authored-by: Mohamed Moustafa <mmoustafa@gitlab.com>