Refactor various ruby files

* Insights based on brakeman report

app/views/application/_breadcrumbs_and_title.html.slim

@@ -1,4 +1,5 @@
-- if model = Kernel.const_get(controller_path.classify) rescue nil
+- model = controller_path.classify.constantize rescue nil
+- if model
   - object = model.find_by(id: params[:id])
   - if model.try(:nested_resource?)
     - root_element = model.model_name.human(count: 2)

app/views/application/_locale_selector.html.slim

@@ -4,4 +4,4 @@ li.nav-item.dropdown
     span.caret
   ul.dropdown-menu.p-0.mt-1 role='menu'
     - I18n.available_locales.sort_by { |locale| t("locales.#{locale}") }.each do |locale|
-      li = link_to(t("locales.#{locale}"), url_for(params.permit!.merge(locale: locale)), 'data-turbolinks' => "false", class: 'dropdown-item')
+      li = link_to(t("locales.#{locale}"), url_for(request.query_parameters.merge(locale: locale)), 'data-turbolinks' => "false", class: 'dropdown-item')