🧪 [Add tests for _select_mirror_strategically]

[marko1olo]

🎯 What: The missing tests for _select_mirror_strategically function

📊 Coverage: All logic branches and conditions such as huggingface mirror selections, random choice paths, and catbox/ru flags.

✨ Result: Increased code coverage.

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PR created automatically by Jules for task 6536948236308042505 started by @marko1olo

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