fix(hip): make() rounds Header Length down for an unpadded raw parameter #1313

Describe the bug
length = total_length // 8 + 4 (hip.py:654) assumes every parameter is already 8-octet aligned, but the bytes branch of _make_hip_param (hip.py:2968-2970) neither pads nor validates the item.

To Reproduce
HIP.__new__(HIP).make(parameters=[b'\x00\x41\x00\x08' + bytes(8)]).pack() (a 12-octet parameter; the constructor path is blocked by D1): Header Length byte is 5 but 52 octets are packed (48 would be consistent). A 7-octet raw parameter gives 4 and 47 octets.

Expected behavior
Pad the raw parameter to a multiple of 8, or reject an unaligned one with ProtocolError.

Found by the internet-v4 round-trip audit (#1202); reproduced on main at 11ae68ebf (repro check D2).

Found by the internet-v4 round-trip audit (#1202). The repro was re-checked by an independent verifier, and I re-ran it on main at 11ae68ebf.