refactor(admissions): do not unpack tuples in hash calculation for admissions extension types

[hoefling]

This is a small improvement for the hash magic methods of the types added for the Admissions extension in #11875. I didn't pay enough attention when doing the initial implementation and overlooked an example of the policy_qualifiers field in PolicyInformation type:

cryptography/src/cryptography/x509/extensions.py

Lines 893 to 901 in 916fd46

	def __hash__(self) -> int:
	if self.policy_qualifiers is not None:
	pq: tuple[str | UserNotice, ...] | None = tuple(
	self.policy_qualifiers
	)
	else:
	pq = None
	return hash((self.policy_identifier, pq))

I amended the methods ProfessionInfo.__hash__(), Admission.__hash__() and Admissions.__hash__() to avoid tuple unpacking and adjusted the none check for profession_oids to have the same logic as the one for the policy_qualifiers. I also removed the type hint from the pq local variable since mypy can infer the types starting with v1.11 (IIRC).