Improve confirmation page

[lebe1]

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

Description

• Add custom confirmation page when purchasing only digital newspaper as item

Checklist:

• I have commented my code (or ChatGPT did), particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings, neither in my IDE nor in my browser
• I have added tests that prove my fix is effective or that my feature works

[lebe1]

@nanu-c I did not check it with the newly added option of buying a digital newspaper and also giving a donation. Could you maybe run this once and show a screenshot as proof?