Refactor MoveTypeEnum into a class

since grpahql 1.10.x no longer supports using
`#define`

doc/api/graphql/reference/gitlab_schema.graphql

@@ -4751,16 +4751,16 @@ enum MilestoneStateEnum {
 }
 
 """
-The position the adjacent object should be moved.
+The position to which the adjacent object should be moved
 """
 enum MoveType {
   """
-  The adjacent object will be moved after the object that is being moved.
+  The adjacent object will be moved after the object that is being moved
   """
   after
 
   """
-  The adjacent object will be moved before the object that is being moved.
+  The adjacent object will be moved before the object that is being moved
   """
   before
 }

doc/api/graphql/reference/gitlab_schema.json

@@ -24316,20 +24316,20 @@
         {
           "kind": "ENUM",
           "name": "MoveType",
-          "description": "The position the adjacent object should be moved.",
+          "description": "The position to which the adjacent object should be moved",
           "fields": null,
           "inputFields": null,
           "interfaces": null,
           "enumValues": [
             {
               "name": "before",
-              "description": "The adjacent object will be moved before the object that is being moved.",
+              "description": "The adjacent object will be moved before the object that is being moved",
               "isDeprecated": false,
               "deprecationReason": null
             },
             {
               "name": "after",
-              "description": "The adjacent object will be moved after the object that is being moved.",
+              "description": "The adjacent object will be moved after the object that is being moved",
               "isDeprecated": false,
               "deprecationReason": null
             }

ee/app/graphql/types/epic_tree/epic_tree_node_input_type.rb

@@ -7,13 +7,6 @@ module Types
       graphql_name 'EpicTreeNodeFieldsInputType'
       description 'A node of an epic tree.'
 
-      MoveTypeEnum = GraphQL::EnumType.define do
-        name 'MoveType'
-        description 'The position the adjacent object should be moved.'
-        value('before', 'The adjacent object will be moved before the object that is being moved.')
-        value('after', 'The adjacent object will be moved after the object that is being moved.')
-      end
-
       argument :id,
                GraphQL::ID_TYPE,
                required: true,

ee/app/graphql/types/move_type_enum.rb

+# frozen_string_literal: true
+
+module Types
+  class MoveTypeEnum < BaseEnum
+    graphql_name 'MoveType'
+    description 'The position to which the adjacent object should be moved'
+
+    value 'before', 'The adjacent object will be moved before the object that is being moved'
+    value 'after', 'The adjacent object will be moved after the object that is being moved'
+  end
+end

ee/spec/graphql/types/move_type_enum_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe GitlabSchema.types['MoveType'] do
+  it { expect(described_class.graphql_name).to eq('MoveType') }
+
+  it 'exposes all the existing move values' do
+    expect(described_class.values.keys).to include(*%w[before after])
+  end
+end