change zero shot widget default example (#7992)

model_cards/facebook/bart-large-mnli/README.md

@@ -3,6 +3,6 @@ license: mit
 thumbnail: https://huggingface.co/front/thumbnails/facebook.png
 pipeline_tag: zero-shot-classification
 widget:
-- text: "November 3 is weeks away and Biden's lead is only growing."
-  labels: "politics, economics, public health, elections"
+- text: "Last week I upgraded my iOS version and ever since then my phone has been overheating whenever I use your app."
+  labels: "mobile, website, billing, account access"
 ---