Sync print label and progress across webapp instances

[sabeechen]

Returns the printing label as part of the status request and the webapp uses that to display printing progress even if it didn't start the print. This means printing could interrupt a label you're currently editing, so I've made the "currently printing" label a separate element. This allows the textbox comes back after printing with whatever you had in it. I also updated the python server simulator to emulate the new behavior.

[andreisperid]

Super cool! And it is really nice that you made this parallel component to keep the previously written text 👏