### Description of the bug When starting a new instance from the `InstanceSelection` view, we don't really handle errors: https://github.com/Altinn/app-frontend-react/blob/b2db477902844d0cfe3d039733f92861b71f158e/src/features/instantiate/selection/InstanceSelection.tsx#L258 ### Steps To Reproduce 1. Use ```json "onEntry": { "show": "select-instance" }, ``` in Application metadata. 2. Get to instance selection 3. Make an `IInstanceValidator` return an issue 4. Click `Start på nytt`-button in instance selection ### Additional Information _No response_