Support GraphQL Variables

Is your feature request related to a problem? Please describe. We're building a GraphQL Endpoint. Checkly allows using GraphQL Queries in API Tests. https://www.checklyhq.com/docs/api-checks/request-settings/ But in Checkly's UI, can't using GraphQL Variables.

Describe the solution you'd like Add a form to write GraphQL Variables.

Describe alternatives you've considered Using JSON body type as a workaround. But, this is painful for me.

original GH issue link https://github.com/checkly/public-roadmap/issues/73