Add missing test for invalid parse_str

[CXWorks]

Hi,

Thanks for your time & patience to review this PR.

We are researchers focusing on Rust unit tests by LLM. By examine the existing code, we found a unit test can be added to improve the repo's overall unit test coverage(this project is already been well tested).
The code region to cover is:

uuid/src/error.rs

Lines 73 to 79 in c889107

	if character as u32 - byte as u32 > 0 {
	// Multibyte char
	return Error(ErrorKind::Char {
	character,
	index: index + offset + 1,
	});
	} else if byte == b'-' {

Thanks again for reviewing.

[KodrAus]

Thanks @CXWorks! Nice catch.