fix: Respond to /api requests as JSON by default
fix: Respond to /api requests as JSON by default

If header 'Accept: application/json' isn't set, the failure
responses to /api endpoints is HTML. Success responses are of type JSON.

StrellaGroup/frappe,frappe/frappe,mhbu50/frappe,mhbu50/frappe,frappe/frappe,almeidapaulopt/frappe,frappe/frappe,yashodhank/frappe,almeidapaulopt/frappe,yashodhank/frappe,saurabh6790/frappe,yashodhank/frappe,almeidapaulopt/frappe,mhbu50/frappe,saurabh6790/frappe,saurabh6790/frappe,StrellaGroup/frappe,saurabh6790/frappe,StrellaGroup/frappe,almeidapaulopt/frappe,mhbu50/frappe,yashodhank/frappe