Fix: Redirect to portal with default locale (#5467)

- Redirect to default locale if URL does not provide the locale param

app/controllers/public/api/v1/portals_controller.rb

@@ -1,5 +1,6 @@
 class Public::Api::V1::PortalsController < PublicController
   before_action :ensure_custom_domain_request, only: [:show]
+  before_action :redirect_to_portal_with_locale, only: [:show]
   before_action :portal
   layout 'portal'
 
@@ -9,5 +10,12 @@ class Public::Api::V1::PortalsController < PublicController
 
   def portal
     @portal ||= Portal.find_by!(slug: params[:slug], archived: false)
+    @locale = params[:locale] || @portal.default_locale
+  end
+
+  def redirect_to_portal_with_locale
+    return if params[:locale].present?
+
+    redirect_to "/hc/#{@portal.slug}/#{@portal.default_locale}"
   end
 end