Use nested_group metadata for subgroup specs

ee/spec/lib/gitlab/insights/finders/issuable_finder_spec.rb

@@ -121,9 +121,8 @@ RSpec.describe Gitlab::Insights::Finders::IssuableFinder do
     end
   end
 
-  context 'for a group' do
+  shared_examples_for 'group tests' do
     let(:entity) { create(:group) }
-    let(:project) { create(:project, :public, group: create(:group, parent: entity)) }
     let(:label_type) { :group_label }
     let(:label_entity_association_key) { :group }
 
@@ -152,6 +151,18 @@ RSpec.describe Gitlab::Insights::Finders::IssuableFinder do
     end
   end
 
+  context 'for a group' do
+    include_examples 'group tests' do
+      let(:project) { create(:project, :public, group: entity) }
+    end
+  end
+
+  context 'for a group with subgroups', :nested_groups do
+    include_examples 'group tests' do
+      let(:project) { create(:project, :public, group: create(:group, parent: entity)) }
+    end
+  end
+
   context 'for a project' do
     let(:project) { create(:project, :public) }
     let(:entity) { project }