[943] Fix issue with passing dates to queued emails
Resolves #943 (closed)
- Update StudentMailer methods to take dates as their string equivalents to avoid a serialization error with ActiveJob. The mailer will convert strings back to Dates to do the formatting as before.
- Fix a typo in the group formation email (period outside of conditional)
Closes #943 (closed)
Blocked on !984 (merged) and !964 (merged).
Edited by Matt Coshal