Fix(test): Mask username field in settings since it's not deterministic. (#8033)

## Summary

Should stop this from flipping back and forth depending on which user
the harness ends up with.

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-8033-Fix-test-Mask-username-field-in-settings-since-it-s-not-deterministic-2e76d73d3650811e85f4fc4ca2253e7e)
by [Unito](https://www.unito.io)

---------

Co-authored-by: github-actions <github-actions@github.com>

src/components/dialog/content/setting/CurrentUserMessage.vue

@@ -7,7 +7,7 @@
     pt:text="w-full"
   >
     <div class="flex items-center justify-between">
-      <div>
+      <div data-testid="current-user-indicator">
         {{ $t('g.currentUser') }}: {{ userStore.currentUser?.username }}
       </div>
       <Button