Bug - invalid sort option in /candidates/totals/ throws 500 error when it should be 422 error

[lbeaufort]

What we’re after

Invalid sort options should return 422 (uprocessible entity) errors like this: https://api.open.fec.gov/v1/candidates/?api_key=DEMO_KEY&sort=-test&per_page=10&sort_hide_null=true&election_full=true&is_active_candidate=true&page=1

This result returns a server error: https://api.open.fec.gov/v1/candidates/totals/?api_key=DEMO_KEY&sort=-test&per_page=10&sort_hide_null=true&election_full=true&is_active_candidate=true&page=1

Action item(s)

• Add validator to args

Completion criteria

• The api returns 422 when user enters invalid sort option