fix: "Add Second Device" not working on Windows

[WofWca]

...because of the firewall sometimes

Closes deltachat/deltachat-desktop#3218

A quick and dirty workaround.
I did not test this directly, except for a prototype app that I made.

[r10s]

thanks for diving into that!

i cannot say much to the code, only to the form: shouldn't that be merged to stable-1.112 so we can do a 1.112.9?

[WofWca]

shouldn't that be merged to stable-1.112 so we can do a 1.112.9?

I'm not familiar with this repo, so it's better if someone else answered this.

[link2xt]

Closing this for now in favor of deltachat/deltachat-desktop#3218
Let's discuss it there if firewall rule can be installed without user action during setup.