Bug: DB secret engine not showing "Select one" in role select options (#11294)

* fix issue on mongo db where the select one was not showing

* add changelog

changelog/11294.txt

@@ -0,0 +1,3 @@
+```release-note:bug
+ui: fix issue where select-one option was not showing in secrets database role creation
+```

ui/app/models/database/role.js

@@ -22,6 +22,7 @@ export default Model.extend({
   }),
   type: attr('string', {
     label: 'Type of role',
+    noDefault: true,
     possibleValues: ['static', 'dynamic'],
   }),
   ttl: attr({