CI-Check for file size fails on all recent branches

Example: https://gitlab.hrz.tu-chemnitz.de/zih/hpcsupport/hpc-compendium/-/jobs/310464

This should not happen. I could think of two possible solutions:

• Do not check files stored in Git LFS
• Shrink files and disallow large files to be added (i.e. remove allow_failure: true from this check)