Install squashfs-tools for mksquashfs

[kazarmy]

Your checklist for this pull request

• I've read the guidelines for contributing to this repository
• I made sure to follow the project's coding style
• I've updated the documentation with the relevant information (if needed)
• I've used AI tools to generate fully or partially these code changes and I'm sure the changes are not copyrighted by somebody else.

Detailed description

This pr installs squashfs-tools in some Linux builds for mksquashfs.

Test plan (required)

All builds are green.

Closing issues

...

[kazarmy]

Surprisingly the linux-x86_64 build is green.

[kazarmy]

The issue with mksquashfs is probably transient.