Have a new dialog message appear on screen while board is connecting #240
Description
Currently when a user tries to connect a board via Web Serial, the same dialog box (Select Serial Device - Connect serial device) remains on screen after a user clicks connect and selects their COM port. This is confusing to users because they aren't sure if a connection is in progress or has failed. The user can also keep clicking the same series of prompts with no feedback. I think it would be helpful to let a user know that the editor is trying to connect to their board that they selected or to tell them that a connection failed.