fix: check for root user as early as possible in landscape-config

[jmucc]

landscape-config must be run as root. We should check that the user is root before trying any operations that would fail anyway.

[Copilot]

Pull request overview

This PR moves the root user check in landscape-config to execute earlier in the execution flow, ensuring the program fails fast with a clear error message before attempting any operations that would fail anyway due to insufficient privileges.

Key Changes:

• Root user validation now occurs immediately after configuration parsing, before any initialization or bootstrap operations
• Test setup updated to mock os.getuid() to return 0 (root) to ensure tests continue passing with the earlier validation

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
landscape/client/configuration.py	Moved root user check from after registration logic to immediately after config parsing and before logging initialization
landscape/client/tests/test_configuration.py	Added os.getuid mocks in test setup classes to simulate root user for existing tests

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.