Style log_rotation_action as radio.

(Looks more aesthetic this way than before).

Author: Maikuolan

assets/config.yml

@@ -7,7 +7,7 @@
 # License: GNU/GPLv2
 # @see LICENSE.txt
 #
-# This file: Configuration defaults file (last modified: 2022.04.04).
+# This file: Configuration defaults file (last modified: 2022.06.01).
 ##/
 
 core:
@@ -33,6 +33,7 @@ core:
   choices:
    Delete: "field_log_rotation_delete"
    Archive: "field_log_rotation_archive"
+  style: "radio"
  timezone:
   type: "timezone"
   default: "SYSTEM"