Split group_import_export_ndjson feature flag

Use one Feature Flat to Group Import and another one to Group Export
to have a more granular control about Group Import/Export with ndjson.

app/services/groups/import_export/export_service.rb

@@ -65,7 +65,7 @@ module Groups
       end
 
       def tree_exporter_class
-        if ::Feature.enabled?(:group_import_export_ndjson, @group&.parent)
+        if ::Feature.enabled?(:group_export_ndjson, @group&.parent)
           Gitlab::ImportExport::Group::TreeSaver
         else
           Gitlab::ImportExport::Group::LegacyTreeSaver

app/services/groups/import_export/import_service.rb

@@ -53,7 +53,7 @@ module Groups
       end
 
       def ndjson?
-        ::Feature.enabled?(:group_import_export_ndjson, @group&.parent) &&
+        ::Feature.enabled?(:group_import_ndjson, @group&.parent) &&
           File.exist?(File.join(@shared.export_path, 'tree/groups/_all.ndjson'))
       end
 

spec/services/groups/import_export/export_service_spec.rb

@@ -50,7 +50,7 @@ describe Groups::ImportExport::ExportService do
     end
 
     it 'saves the models using ndjson tree saver' do
-      stub_feature_flags(group_import_export_ndjson: true)
+      stub_feature_flags(group_export_ndjson: true)
 
       expect(Gitlab::ImportExport::Group::TreeSaver).to receive(:new).and_call_original
 
@@ -58,7 +58,7 @@ describe Groups::ImportExport::ExportService do
     end
 
     it 'saves the models using legacy tree saver' do
-      stub_feature_flags(group_import_export_ndjson: false)
+      stub_feature_flags(group_export_ndjson: false)
 
       expect(Gitlab::ImportExport::Group::LegacyTreeSaver).to receive(:new).and_call_original
 

spec/services/groups/import_export/import_service_spec.rb

@@ -3,7 +3,7 @@
 require 'spec_helper'
 
 describe Groups::ImportExport::ImportService do
-  context 'with group_import_export_ndjson feature flag disabled' do
+  context 'with group_import_ndjson feature flag disabled' do
     let(:user) { create(:admin) }
     let(:group) { create(:group) }
     let(:import_logger) { instance_double(Gitlab::Import::Logger) }
@@ -11,7 +11,7 @@ describe Groups::ImportExport::ImportService do
     subject(:service) { described_class.new(group: group, user: user) }
 
     before do
-      stub_feature_flags(group_import_export_ndjson: false)
+      stub_feature_flags(group_import_ndjson: false)
 
       ImportExportUpload.create(group: group, import_file: import_file)
 
@@ -39,9 +39,9 @@ describe Groups::ImportExport::ImportService do
     end
   end
 
-  context 'with group_import_export_ndjson feature flag enabled' do
+  context 'with group_import_ndjson feature flag enabled' do
     before do
-      stub_feature_flags(group_import_export_ndjson: true)
+      stub_feature_flags(group_import_ndjson: true)
     end
 
     context 'when importing a ndjson export' do