Handle Bitswap messages without Wantlist

[dmitry-markin]

Correctly handle Bitswap protobuf messages without Wantlist field.

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[codecov]

Codecov Report

Attention: Patch coverage is 50.00000% with 6 lines in your changes missing coverage. Please review.

Project coverage is 61.58%. Comparing base (1f89f55) to head (e083031).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
bitswap/message/message.go	50.00%	4 Missing and 2 partials ⚠️

@@            Coverage Diff             @@
##             main     #961      +/-   ##
==========================================
- Coverage   61.61%   61.58%   -0.04%     
==========================================
  Files         254      254              
  Lines       31425    31427       +2     
==========================================
- Hits        19363    19354       -9     
- Misses      10489    10499      +10     
- Partials     1573     1574       +1     

Files with missing lines	Coverage Δ
bitswap/message/message.go	81.41% <50.00%> (+0.11%)	⬆️

... and 12 files with indirect coverage changes

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