fix image similarity detection

src/streamlit_app.py

@@ -173,7 +173,7 @@ if query:
         else:
             st.warning("OpenAI API key not found. Please set OPENAI_API_KEY as a secret environment variable.")
 
-if uploaded_file is not None:
+if uploaded_file:
     with st.spinner("Searching medical cases..."):
         print(uploaded_file)
         st.write(f'uploading file {uploaded_file.name}')