fix: Add missing empty credential libraries message

ui/admin/app/templates/scopes/scope/targets/target/add-credential-libraries.hbs

@@ -7,4 +7,21 @@
     @submit={{route-action 'save' @model.target}}
     @cancel={{route-action 'cancel'}}
   />
-{{/if}}
+{{/if}}
+
+{{#unless @model.credentialLibraries}}
+  <Rose::Layout::Centered>
+    <Rose::Message
+      @title={{t 'resources.target.credential-library.messages.none.title'}}
+      as |message|
+    >
+      <message.description>
+        {{t 'resources.target.credential-library.messages.none.description'}}
+      </message.description>
+      <message.link @route='scopes.scope.targets.target.credential-libraries'>
+        <Rose::Icon @name='chevron-left' />
+        {{t 'actions.back'}}
+      </message.link>
+    </Rose::Message>
+  </Rose::Layout::Centered>
+{{/unless}}