SAUL uses deprecated `saul_class_to_str` function

[leandrolanzieri]

During a cleanup of deprecated items in RIOT (RIOT-OS/RIOT#21985), I attempted to remove the deprecated function saul_class_to_str from SAUL. This resulted in the CI pointing out that this crate is using it. I ended up reverting the change because I'm not familiar with the workflow of addressing this changes on the rust code base, nor how to implement name using the non-deprecated variants. I guess the change would require changing the API to receive a buffer?

The usage is here:

rust-riot-wrappers/src/saul/mod.rs

Lines 300 to 306 in 833f768

	/// Human-readable name of the class
	pub fn name(self) -> Option<&'static str> {
	unsafe { riot_sys::saul_class_to_str(self.to_c()).to_lifetimed_cstr()? }
	.to_str()
	.ok()
	}
	}