[4.0] Fix showOn for select field with multiple attr (#35723)

Author: dgrammatiko

build/media_source/system/joomla.asset.json

@@ -99,14 +99,27 @@
       "uri": ""
     },
     {
-      "name": "showon",
+      "name": "showon.es5",
       "type": "script",
       "dependencies": [
         "core"
       ],
+      "uri": "system/showon-es5.min.js",
+      "attributes": {
+        "defer": true,
+        "nomodule": true
+      }
+    },
+    {
+      "name": "showon",
+      "type": "script",
+      "dependencies": [
+        "core",
+        "showon.es5"
+      ],
       "uri": "system/showon.min.js",
       "attributes": {
-        "defer": true
+        "type": "module"
       }
     },
     {