added file error handling

app.py

@@ -20,6 +20,7 @@ def handle_submit():
                 assessment_item_coding_tasks[i]["candidate_solution"] = st.session_state["file_upload_"+str(i+1)].read().decode("utf-8")
             except:
                 st.error("Please upload a valid code file")
+                return
     upsert_item = st.session_state["assessment_db_object"]
     upsert_item["coding_tasks"] = assessment_item_coding_tasks
     container.upsert_item(upsert_item)