Signup wizard: preview step should include useful example (not just placeholder)

[msavy]

Problem description

In the highlighted segments we only show a placeholder. Instead, we should still consider showing the technical aspects so that the user can understand what they need to do

For example, X-Api-Key: <Key generated on signup>

Acceptance criteria

• Provide example with placeholder where key would be

[volkflo]

@msavy That is fully customizable in the i18n files, but agree.
We can provide a more useful default template.