Move epic field in GraphQL IssueType

Fixes broken master in gitlab-foss

app/graphql/types/issue_type.rb

@@ -49,7 +49,6 @@ module Types
     field :web_url, GraphQL::STRING_TYPE, null: false # rubocop:disable Graphql/Descriptions
     field :relative_position, GraphQL::INT_TYPE, null: true # rubocop:disable Graphql/Descriptions
 
-    field :epic, ::Types::EpicType, null: true, description: 'The epic to which issue belongs'
     field :participants, Types::UserType.connection_type, null: true, complexity: 5, description: 'List of participants for the issue'
     field :time_estimate, GraphQL::INT_TYPE, null: false, description: 'The time estimate on the issue'
     field :total_time_spent, GraphQL::INT_TYPE, null: false, description: 'Total time reported as spent on the issue'

ee/app/graphql/ee/types/issue_type.rb

@@ -6,6 +6,8 @@ module EE
       extend ActiveSupport::Concern
 
       prepended do
+        field :epic, ::Types::EpicType, null: true, description: 'The epic to which issue belongs'
+
         field :weight, GraphQL::INT_TYPE, # rubocop:disable Graphql/Descriptions
               null: true,
               resolve: -> (obj, _args, _ctx) { obj.supports_weight? ? obj.weight : nil }

ee/spec/graphql/types/issue_type_spec.rb

@@ -3,6 +3,8 @@
 require 'spec_helper'
 
 describe GitlabSchema.types['Issue'] do
+  it { expect(described_class).to have_graphql_field(:epic) }
+
   it { expect(described_class).to have_graphql_field(:weight) }
 
   it { expect(described_class).to have_graphql_field(:designs) }

spec/graphql/types/issue_type_spec.rb

@@ -10,7 +10,7 @@ describe GitlabSchema.types['Issue'] do
   it { expect(described_class.interfaces).to include(Types::Notes::NoteableType.to_graphql) }
 
   it 'has specific fields' do
-    fields = %i[iid title description state reference author assignees participants labels epic milestone due_date
+    fields = %i[iid title description state reference author assignees participants labels milestone due_date
                 confidential discussion_locked upvotes downvotes user_notes_count web_path web_url relative_position
                 time_estimate total_time_spent closed_at created_at updated_at task_completion_status]