Ballot PDF generation is broken (also on demosystem)

[AnanasPizza]

Describe the bug
When creating ballots from an election, the pdf is badly formatted. Lots of empty space, sometimes whole empty pages.

How to Reproduce

1. Used this demo system and created a ballot paper here:
   https://demo.openslides.org/18/assignments/3
2. Look at broken PDF (also attached)

Expected behavior

A well formatted PDF, without empty pages between, or duplicated lines.

System information

• OpenSlides version: 4.2.29 (2026-01-17)
• Additional version information (if any): [e.g. commit hash or month of installation]
• Device: Notebook
• OS: Windows 11
• Browser: Chrome

Additional context

Wahl - Wahl des Vorstandes - stimmzettel.pdf

Screenshots
If applicable, add screenshots to help explain your problem. I think something is wrong with the logic that calculates the layout of the pdf.

[Elblinator]

This is a client is issue (why I moved it to the client) and right now we finalise the newest big version so we cannot look at this issue for now