Let the system find the right icon

[ArchangeGabriel]

This allow themes to replace it, and makes use of the .svg one installed under hicolor by default.

[raelgc]

@ArchangeGabriel The icon was intentionally forced to be the colored one in the desktop (just the systray ones are following the system theme).

In the other side, this will allow easy theming. Let me think a bit about it.

[ArchangeGabriel]

Well I admit having not checked the svg icon, I blindly assumed it was the same and did not realize my mistake because I had this one instead: https://github.com/PapirusDevelopmentTeam/papirus-icon-theme/blob/master/Papirus/64x64/apps/slack.svg

[ArchangeGabriel]

Can you not set the tray icon from elsewhere? Other apps like Mattermost don’t have this issue.