Fix OpenStruct use in connection_spec

.rubocop_todo/style/open_struct_use.yml

@@ -38,7 +38,6 @@ Style/OpenStructUse:
   - spec/lib/gitlab/database/migrations/runner_spec.rb
   - spec/lib/gitlab/gitaly_client/blobs_stitcher_spec.rb
   - spec/lib/gitlab/gitaly_client/diff_stitcher_spec.rb
-  - spec/lib/gitlab/graphql/pagination/keyset/connection_spec.rb
   - spec/lib/gitlab/legacy_github_import/project_creator_spec.rb
   - spec/lib/gitlab/quick_actions/command_definition_spec.rb
   - spec/models/design_management/design_action_spec.rb

spec/lib/gitlab/graphql/pagination/keyset/connection_spec.rb

@@ -7,7 +7,7 @@ RSpec.describe Gitlab::Graphql::Pagination::Keyset::Connection do
   let(:arguments) { {} }
   let(:query_type) { GraphQL::ObjectType.new }
   let(:schema) { GraphQL::Schema.define(query: query_type, mutation: nil)}
-  let(:context) { GraphQL::Query::Context.new(query: OpenStruct.new(schema: schema), values: nil, object: nil) }
+  let(:context) { GraphQL::Query::Context.new(query: double('query', schema: schema), values: nil, object: nil) }
 
   subject(:connection) do
     described_class.new(nodes, **{ context: context, max_page_size: 3 }.merge(arguments))