Upgrade build scripts to Fedora 43

[Copilot]

Updates the Fedora Remix for WSL build infrastructure to target Fedora 43, following the established version upgrade pattern.

Changes

• Version configuration: Updated default version from 42 to 43 in create-targz.sh and debootstrap_architecture_template.yml
• Release metadata: Added os-release-43 with VERSION_ID=43, PLATFORM_ID="platform:f43", FEDORA_REMIX_VERSION=43.0.0
• MESA drivers: Added fc43 entry (25.1.0-1_wsl_4.fc43) to mesa_version arrays in create-targz.sh and upgrade.sh
• Package repositories: Updated wslu copr logic to use fedora-42 repo for VERSION_ID > 42

Notes

The MESA version string follows the existing increment pattern and may need adjustment based on actual package availability in the WhitewaterFoundry repository.

Original prompt

This is a repo with the script to build the distribution, Fedora Remix for WSL. Check previous commits and make the neccessary changes to upgrade the scripts to create the Fedora 43 image

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