chore(icons): change heroicons from v1 to v2

[spark-sse]

Laut deren Release-Seite [1] ist die v1 Version nicht die "alte", wird aber dennoch nicht weiter gepflegt und immer wieder würden wir gerne Icons aus der v2 verwenden.

Ein update auf v2 wurde durchgeführt. entsprechend ähnliche icons wurden verwendet.

[1]

Heroicons v2.0 is a brand new icon set with a different visual style, so don't feel like you need to upgrade to avoid "being on the old version".
If you like how the v1 icons look in your project, stick with them! Heroicons v2 is more like Terminator 2 than OpenSSL 2 — they represent our best work but these are just little SVG pictures, the version you choose to use is personal preference, not a technical decision.
If you do want to upgrade to v2, understand that because it's an all-new icon set, switching to Heroicons v2 is more like migrating to a new icon set than it is just updating a dependency in your project. We've tried to make it pretty smooth, but because it's a new set, a lot things like import paths and icon names have changed, so there is some manual work involved in migrating.