T&A 0040337 Fix zero input on file upload questions

[kunzeus]

https://mantis.ilias.de/view.php?id=40337

should prevent people from creating zero point file upload questions

Same code on ILIAS 7, 8, 9 Tested on ILIAS 7, 8

[dsstrassner]

If the JF in Mantis 40337 agrees, this is the associated fix.

[matthiaskunkel]

Jour Fixe, 19 FEB 2024: We highly appreciate this PR and accept it for 7, 8, 9 and trunk.

[thojou]

hey @kunzeus,

I have reviewed your changes and incorporated them into ILIAS versions 8, 9, and trunk. I will close this PR for release_7 because, as mentioned in the Mantis ticket by @dsstrassner, ILIAS 7 has reached its end of life and will no longer be maintained.

Thank you for your efforts!