hsfz: Fix acknowledgment transfer packet structure.

[antoniovazquezblanco]

Checklist:

• If you are new to Scapy: I have checked CONTRIBUTING.md (esp. section submitting-pull-requests)
• I squashed commits belonging together
• I added unit tests or explained why they are not relevant
• I executed the regression tests (using cd test && ./run_tests or tox)
• If the PR is still not finished, please create a Draft Pull Request

Fixes ACK packet structure in HSFZ.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 82.16%. Comparing base (6c658dd) to head (86235ec).
Report is 1 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #4758      +/-   ##
==========================================
+ Coverage   79.52%   82.16%   +2.64%     
==========================================
  Files         344      362      +18     
  Lines       87082    87359     +277     
==========================================
+ Hits        69251    71778    +2527     
+ Misses      17831    15581    -2250     

Files with missing lines	Coverage Δ
scapy/contrib/automotive/bmw/hsfz.py	62.24% <100.00%> (+0.78%)	⬆️

... and 289 files with indirect coverage changes

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[polybassa]

Thanks for the PR!

[antoniovazquezblanco]

Lovely, Thank you! :D