color cannot be changed if imported story already contains colored icons

[hofstef]

Describe the bug
Error message:

ERROR TypeError: b is undefined
rgbaToHex colorConverter.ts:5
getSelectedBusinessObject domainStoryContextPadProvider.js:342
executeCommandStack domainStoryContextPadProvider.js:353
DomainStoryContextPadProvider domainStoryContextPadProvider.js:47
Angular 10
onColorChanged app.component.ts:161
AppComponent_Template_input_colorPickerClose_1_listener app.component.html:7
Angular 13

To Reproduce

1. Import from URL: https://github.com/WPS/egon.io-examples/blob/main/examples%20from%20the%20book/alphorn%20car%20leasing/en/alphorn-5a-riskassessment-fine-digitalized-tobe-colored.dst
2. Select actor 'online leasing service'
3. Open color picker from context pad
4. Select a new color and click on canvas to apply => new color is not applied, console shows error message

Version

• Egon: v2.3.0, v2.4.0-dev
• Browser: Firefox