Try to fix flaky tests

ee/spec/lib/ee/gitlab/import_export/group_tree_saver_spec.rb

@@ -41,7 +41,11 @@ describe Gitlab::ImportExport::GroupTreeSaver do
       it 'saves parent of epic' do
         expect_successful_save(group_tree_saver)
 
-        parent = saved_group_json['epics'].first['parent']
+        child = saved_group_json['epics'].find do |attrs|
+          attrs['id'] == epic.id
+        end
+
+        parent = child['parent']
 
         expect(parent).not_to be_empty
         expect(parent['id']).to eq(parent_epic.id)
@@ -50,7 +54,11 @@ describe Gitlab::ImportExport::GroupTreeSaver do
       it 'saves epic notes' do
         expect_successful_save(group_tree_saver)
 
-        notes = saved_group_json['epics'].first['notes']
+        child = saved_group_json['epics'].find do |attrs|
+          attrs['id'] == epic.id
+        end
+
+        notes = child['notes']
 
         expect(notes).not_to be_empty
         expect(notes.first['note']).to eq(note.note)