chore: test that the tags API still returns tags that you can't create anymore (#7304)

This change adds a test to the tags API to ensure that even if you
can't create tags that are pure whitespace anymore, you'll still
receive pre-existing tags from the API that fit this description.

The test is here to ensure that we don't break this in future versions
of Unleash.

Author: thomasheartman

src/test/e2e/api/admin/tags.e2e.test.ts

@@ -209,3 +209,10 @@ test('Can bulk remove tags', async () => {
         })
         .expect(200);
 });
+
+test('backward compatibility: the API should return invalid tag names if they exist', async () => {
+    const tag = { value: '  ', type: 'simple' };
+    await db.stores.tagStore.createTag(tag);
+    const { body } = await app.request.get('/api/admin/tags').expect(200);
+    expect(body.tags).toContainEqual(tag);
+});