implement a state check function

Being able to validate FT application state would help increase the reliability in the server behavior. Should see what properties can be checked to find the following:

• FT is open/in focus
• FT is in a call lobby (pre-join)
• FT is in a call, with sidebar closed
• FT is in a call, with the sidebar open (this is preferable)

This could be then used to validate calls are joined/left correctly, as well as determine if APIs are being called in the right order.