fix #3442

[yangyingchao]

I'm not sure if this is a proper fix; please have it reviewed before merging.

[khaneliman]

Worked here locally to fix the issue, thanks!

[RobertMueller2]

I've tested it too and it fixes all the problems I've seen with the module. I think this might also address #3430 and #3310.

I can't help but wonder if looking at this

Waybar/src/modules/sni/tray.cpp

Line 22 in 3f61df4

nb_hosts_ += 1;

might avoid the situation altogether. nb_hosts_ is a static variable that will be used for Host's id which ensures multi monitor trays will have unique ids but when running more than one instance of waybar of course it isn't globally unique. And other programs having a tray might also just start from 0. I don't have a suggestion how to deal with it, and I don't mean to stop the PR. I've not seen any problems with it, either. Just wanted to leave this here in case somebody picks up more work on the module in the future.

[Alexays]

LGTM, thx!