Fix: [CMake] remove cpack warning on fedora when lsb_release exists

[bc-lee]

Motivation / Problem

I'm currently using Fedora 37 and I get errors like this:

CMake Warning at cmake/InstallAndPackage.cmake:194 (message):
  Unknown LSB-based Linux distribution 'Fedora' found for packaging; can only
  pack to a txz.  Please consider creating a Pull Request to add support for
  this distribution.

So, I'd like to remove the warning. (BTW, I don't use cpack to install locally-modified openttd.)

Description

Limitations

Checklist for review

Some things are not automated, and forgotten often. This list is a reminder for the reviewers.

• The bug fix is important enough to be backported? (label: 'backport requested')
• This PR touches english.txt or translations? Check the guidelines
• This PR affects the save game format? (label 'savegame upgrade')
• This PR affects the GS/AI API? (label 'needs review: Script API')
  • ai_changelog.hpp, gs_changelog.hpp need updating.
  • The compatibility wrappers (compat_*.nut) need updating.
• This PR affects the NewGRF API? (label 'needs review: NewGRF')
  • newgrf_debug_data.h may need updating.
  • PR must be added to API tracker