Fix handling of JSON payload in API auth tests

Rails 7 appears to apply stricter parsing rules. If the Content-Type is not JSON, then the body will not be parsed as JSON.

spec/requests/api/v1/authentication_controller_spec.rb

@@ -20,22 +20,22 @@
 
       it 'calls the Api::Jwt::AuthenticationService' do
         Api::V1::Auth::Jwt::AuthenticationService.any_instance.expects(:call).at_most(1)
-        post api_v1_authenticate_path, params: @payload.to_json
+        post api_v1_authenticate_path, params: @payload, as: :json
       end
       it 'renders /api/v1/error template if authentication fails' do
         errs = [Faker::Lorem.sentence]
         Api::V1::Auth::Jwt::AuthenticationService.any_instance
                                                  .stubs(:call).returns(nil)
                                                  .stubs(:errors).returns(errs)
-        post api_v1_authenticate_path, params: @payload.to_json
+        post api_v1_authenticate_path, params: @payload, as: :json
         expect(response.code).to eql('401')
         expect(response).to render_template('api/v1/error')
       end
       it 'returns a JSON Web Token' do
         token = Api::V1::Auth::Jwt::JsonWebToken.encode(payload: @payload)
         Api::V1::Auth::Jwt::AuthenticationService.any_instance.stubs(:call)
                                                  .returns(token)
-        post api_v1_authenticate_path, params: @payload.to_json
+        post api_v1_authenticate_path, params: @payload, as: :json
         expect(response.code).to eql('200')
         expect(response).to render_template('api/v1/token')
       end