Handle error 500 on when null is provided as root field value and content-type is set to application/json Ref T1122
Summary: Ref T1122
Test Plan: make test oraz wysłać POST z JSONem na wybrany zasób z ustawionym application/json dla content-type i wartością null dla jakiegoś rootowego field type'a
Reviewers: kuba-orlik, #sealious_devs, #reviewers
Reviewed By: kuba-orlik, #sealious_devs, #reviewers
Subscribers: #sealious_devs
Maniphest Tasks: T1122
Differential Revision: https://hub.sealcode.org/D387