Fix typo since the tab is not showing, it should be `Tab` not `tab`

callbackmanager.py

@@ -318,7 +318,7 @@ with gr.Blocks() as demo:
             outputs=[meldrx_pdf_download, meldrx_pdf_status]
         )
 
-    with gr.tab("Show Patients Log"):
+    with gr.Tab("Show Patients Log"):
         gr.Markdown("## Patient Dashboard")
 
         # Store patient data in a state variable