OZG-5842 OZG-5851 Use dedicated input properties for first and second text line

alfa-client/apps/demo/src/app/app.component.html

.../lib/button-with-spinner/button-with-spinner.component.ts

...lib/form/validation-error/validation-error.component.html

...tem/src/lib/form/error-message/error-message.component.ts

...ystem/src/lib/form/error-message/error-message.stories.ts