[CLI] No traceback on LocalEntryNotFoundError

[Wauplin]

With this PR:

$ HF_HUB_OFFLINE=1 hf download gpt2 config.json
Error: Local entry not found. Cannot reach https://huggingface.co/gpt2/resolve/main/config.json: offline mode is enabled. To disable it, please unset the `HF_HUB_OFFLINE` environment variable.
Set HF_DEBUG=1 as environment variable for full traceback.

cc @julien-c

---

Note

Low Risk
Low risk: changes are limited to CLI exception-to-message formatting and should not affect core download behavior. Main risk is minor messaging/regression in which exception gets matched/printed for offline/local-cache error cases.

Overview
Improves CLI error formatting for offline/local-cache download scenarios by handling LocalEntryNotFoundError explicitly and printing a concise message (preferring the underlying __cause__) instead of a traceback.

Adds OfflineModeIsEnabled to the known-exception mapping so offline-mode errors also render cleanly via format_known_exception.

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[bot-ci-comment]

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