Remote media type detection fails when servers reject HEAD requests

Description

Image.from_url() and Audio.from_url() probe the content type for extensionless remote URLs using a HEAD request. Some servers serve the media normally with GET but return 405 Method Not Allowed or 501 Not Implemented for HEAD.

In that case, probe_remote_content_type() raises requests.HTTPError, so otherwise valid remote media cannot be classified or used.

Expected behavior

When HEAD returns 405 or 501, retry the probe with a streamed GET request and inspect its Content-Type header. Other HTTP errors should still be raised.

The fallback should retain the existing URL validation, redirect validation, DNS/SSRF protections, peer verification, timeout, and resource cleanup.

Verification

I reproduced this against the current main branch and have a focused patch with regression coverage for:

• HEAD 405 followed by a successful GET
• HEAD 501 followed by a successful GET
• no retry for unrelated errors such as 404

Is a PR welcome?