Better waiting message for record generation test

app.py

@@ -630,7 +630,8 @@ def create_ui():
                 <div class="loading-spinner"></div>
                 <div>
                     <div>Running records generation test...</div>
-                    <div>This test tries to load a sample of the data and may be slow for large datasets.</div>
+                    <div>This test tries to load your data and may be slow for large datasets.</div>
+                    <div>It's not strictly required to pass this test to submit to NeurIPS. You can still submit your Croissant file if this test takes too long.</div>
                 </div>
             </div>
             """