fix(protocol): a raw-bytes or Schema item in a make() list crashes construction #1312

Describe the bug
Protocol.__init__ stores the made schema in __header__ (protocol.py:573) and unpack then reuses it instead of re-parsing (protocol.py:593-596), so read receives items still as bytes/Schema. The bytes/Schema items that _make_hip_param, _make_ipv4_options and _make_mh_options accept are not readable by read.

To Reproduce

• HIP(extension=True, parameters=[b'\x00\x41\x00\x08' + bytes(8)]): AttributeError: 'bytes' object has no attribute 'type' at hip.py:786
• IPv4(options=[b'\x94\x04\x00\x00'], protocol=253): same error at ipv4.py:621
• MH(data={'options': [b'\x01\x02\x00\x00']}): same at mh.py:2824
• bare MH(): 'bytes' object has no attribute 'options' at mh.py:1678 (the default is data=b'\x00\x00', mh.py:1448)

Expected behavior
Items the makers accept build a packet, and a bare MH() constructs. Either re-parse the packed header in unpack or have read accept the made schema.

Found by the internet-v4 round-trip audit (#1202); reproduced on main at 11ae68ebf (repro check D1).

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.