Hello,
Here is my solution in a few line of code after having installed the correct module
pip install streamlit-javascript
pip install pyyaml ua-parser user-agents
After that in your main code
from streamlit_javascript import st_javascript
from user_agents import parse
.....
main()
ua_string = st_javascript("""window.navigator.userAgent;""")
user_agent = parse(ua_string)
st.session_state.is_session_pc = user_agent.is_pc
st.info(st.session_state.is_session_pc)
user_agent.is_pc returns True if the session runs on a PC. I then used that to conditionally render some data or not if the User is not running from a PC.
Can also potentially help to prevent the execution of your Streamlit Apps by Bots or other automatic agents.
More info on the packages installed here:
Hope this will be helpful! 
Cheers,
Pascal