Fix Error 500 when updating a project

If no parameters were specified for project features but Wikis were disabled,
we would get "NoMethodError: undefined method `[]' for nil:NilClass".

Closes #44019

app/services/projects/update_service.rb

@@ -58,7 +58,7 @@ module Projects
     def enabling_wiki?
       return false if @project.wiki_enabled?
 
-      params[:project_feature_attributes][:wiki_access_level].to_i > ProjectFeature::DISABLED
+      params.dig(:project_feature_attributes, :wiki_access_level).to_i > ProjectFeature::DISABLED
     end
 
     def ensure_wiki_exists

spec/services/projects/update_service_spec.rb

@@ -132,6 +132,15 @@ describe Projects::UpdateService do
         expect(result).to eq({ status: :success })
         expect(project.wiki_repository_exists?).to be false
       end
+
+      it 'handles empty project feature attributes' do
+        project.project_feature.update(wiki_access_level: ProjectFeature::DISABLED)
+
+        result = update_project(project, user, { name: 'test1' })
+
+        expect(result).to eq({ status: :success })
+        expect(project.wiki_repository_exists?).to be false
+      end
     end
 
     context 'when enabling a wiki' do