[WIP] fix(auth): auto-detect non-RSA private keys in service account info

[ohmayr]

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Fixes #<issue_number_goes_here> 🦕

[gemini-code-assist]

Code Review

This pull request introduces auto-detection for non-RSA (EC) keys when parsing service account info, automatically switching to an EC signer if "EC PRIVATE KEY" or "EC PARAMETERS" is detected in the private key. A corresponding test case is added to verify this behavior. The reviewer suggested improving the auto-detection logic to also handle bytes types for the private key by decoding them to UTF-8 before performing substring checks.

[gemini-code-assist]

The current auto-detection logic only checks if private_key is an instance of str. However, in Python, private_key can also be passed as bytes (which is supported by crypt.RSASigner.from_string and crypt.EsSigner.from_string). If private_key is bytes, the check isinstance(private_key, str) will evaluate to False, and the auto-detection will fail, leading to a subsequent failure when attempting to load the key as RSA.

To make this more robust, we should decode private_key to a string if it is an instance of bytes before performing the substring checks.

Suggested change

	private_key = data.get("private_key", "")
	if (
	use_rsa_signer
	and isinstance(private_key, str)
	and ("EC PRIVATE KEY" in private_key or "EC PARAMETERS" in private_key)
	):
	use_rsa_signer = False
	private_key = data.get("private_key", "")
	if use_rsa_signer:
	if isinstance(private_key, bytes):
	private_key = private_key.decode("utf-8", errors="ignore")
	if isinstance(private_key, str) and (
	"EC PRIVATE KEY" in private_key or "EC PARAMETERS" in private_key
	):
	use_rsa_signer = False