Allow require_graphql_authorizations to work for mutations

We should fix require_graphql_authorizations so that we can test permissions required in mutations easily.

We currently get:

NameError: undefined local variable or method `field' for #<RSpec::Matchers::DSL::Matcher require_graphql_authorizations>
Did you mean?  yield
from /Users/seanarnold/.rvm/gems/ruby-2.6.5/gems/rspec-expectations-3.9.1/lib/rspec/matchers.rb:963:in `method_missing'

When trying to use it with mutations.