add tags story that ensures !test tag is respected

Author: JReinhold

tests/stories/Tags.stories.svelte

@@ -11,14 +11,23 @@
     parameters: {
       controls: { disable: true },
     },
-    tags: ['!dev', '!autodocs', '!test'],
+    tags: ['custom-tag'],
   });
 </script>
 
 <Story name="With Autodocs" tags={['autodocs']}>With autodocs</Story>
 
-<Story name="With Dev" tags={['dev']}>With dev</Story>
+<Story name="Without Dev" tags={['!dev', 'autodocs']}>Without dev</Story>
 
-<Story name="With Test" tags={['test']}>With test</Story>
+<Story
+  name="Without Test"
+  tags={['!test']}
+  play={() => {
+    throw new Error('This error is on purpose');
+  }}
+>
+  This story fails interaction testing, but should not run in Vitest because it has the
+  <code>"!test"</code> tag.
+</Story>
 
-<Story name="No Tags">No tags</Story>
+<Story name="No story-level tags">No story-level tags</Story>