IsoTpMessage: extend timeout on first frame response

[sshane]

Try 2 of #1487 and #1610. Potentially fixes commaai/openpilot#32242

In short, this adds checks to first and single ISO-TP frame types. If you receive a first frame, the next message must be consecutive, or the new assertions in first and single are raised. You can receive as many single frames as you want without issue.

An additional rx length check is added to ensure that rx_dat isn't unset in the first frame hook (it previously accepted m._isotp_rx_next(b'\x10\x08')) which isn't a valid CAN frame size.

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This would cause the EPS to now successfully respond for:

• 297b4b460f361603/2023-06-14--16-55-16
• 297b4b460f361603/2023-06-14--16-48-52
• 297b4b460f361603/2023-06-21--04-09-15

[sshane]

Cases we need to handle for VW:

• case 1:
  • single frame: error code 0x78
  • some time later: first frame, consecutive frame, etc.
• case 2:
  • single frame: error code 0x78
  • some time later, single frame

cases that should pass:

• case 1:
  • single frame
  • single frame
  • etc.
• case 2:
  • single frame
  • first frame
• case 3:
  • first frame
  • consecutive frame(s)
  • first/single frame

cases that should fail:

• case 1:
  • first frame
  • first frame
  • etc.
• case 2
  • first frame
  • single frame