fix failing tests due to new group visibility restrictions

spec/features/projects/new_project_spec.rb

@@ -87,7 +87,7 @@ feature 'New project' do
     end
 
     context 'with subgroup namespace' do
-      let(:group) { create(:group, :private, owner: user) }
+      let(:group) { create(:group, owner: user) }
       let(:subgroup) { create(:group, parent: group) }
 
       before do

spec/models/group_spec.rb

@@ -127,7 +127,7 @@ describe Group do
           internal_group.visibility_level = Gitlab::VisibilityLevel::PRIVATE
 
           expect(internal_group).to be_invalid
-          expect(internal_group.errors[:visibility_level]).to include('private is not allowed since there are projects with higher visibility.')
+          expect(internal_group.errors[:visibility_level]).to include('private is not allowed since this group contains projects with higher visibility.')
         end
       end
 
@@ -149,7 +149,7 @@ describe Group do
           internal_group.visibility_level = Gitlab::VisibilityLevel::PRIVATE
 
           expect(internal_group).to be_invalid
-          expect(internal_group.errors[:visibility_level]).to include('private is not allowed since there are sub groups with higher visibility.')
+          expect(internal_group.errors[:visibility_level]).to include('private is not allowed since there are sub-groups with higher visibility.')
         end
       end