Custom color for button with mode "go-to-task"

### Description

If you use the mode "go-to-task" the button will have the defualt styling with white background and blue text.

It would be nice to have the option to change the colors to something else.
This is because this button is created to go to a different task, that might be to end the process of the application, aka. submit the form.

### Additional Information

_No response_

The issue names no files, tests, or entry points. Start by locating the button implementation and the "go-to-task" mode in the TypeScript React frontend, then inspect how its default colors are assigned. Done means that this mode supports changing its button colors without breaking the existing default styling.

Written by the indexing model from the issue text.