When a /join submitter's email matches a pending/selected/invited
PreRegistration, mark the pre-reg as accepted and link memberId to the
new Member. Prevents the same person from appearing as both an active
member and an unaccepted pre-registrant. Silent — no email, no UI.
Adds the PreRegistration mock to helcim-customer and free-signup-flow
test suites, since both invoke the customer handler at runtime.
Jennie Robinson Faber
da5e7efcb7