Delete not used translation

addons/core/translations/resources/en-us.yaml

@@ -267,4 +267,3 @@ target:
       add:
         title: Add Host Sets
         description: Select host sets to assign to this target.
-    secret: ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■