Include subgroups when fiunding Insights issuables

Signed-off-by: Rémy Coutable <remy@rymai.me>

ee/changelogs/unreleased/11112-insights-charts-don-t-load-data-from-subgroups-of-a-top-level-group.yml

+---
+title: Include subgroups when finding Insights issuables
+merge_request: 10801
+author:
+type: fixed

ee/lib/gitlab/insights/finders/issuable_finder.rb

@@ -49,6 +49,7 @@ module Gitlab
 
         def finder_args
           {
+            include_subgroups: true,
             state: opts[:issuable_state] || 'opened',
             label_name: opts[:filter_labels],
             sort: 'created_asc',

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

@@ -123,7 +123,7 @@ RSpec.describe Gitlab::Insights::Finders::IssuableFinder do
 
   context 'for a group' do
     let(:entity) { create(:group) }
-    let(:project) { create(:project, :public, group: entity) }
+    let(:project) { create(:project, :public, group: create(:group, parent: entity)) }
     let(:label_type) { :group_label }
     let(:label_entity_association_key) { :group }