LengthString deserialize fix

[mappum]

This PR fixes LengthString always setting a length of 0 when deserializing.

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 11 lines in your changes missing coverage. Please review.

Project coverage is 56.93%. Comparing base (ff7eab1) to head (296a691).
Report is 5 commits behind head on develop.

Files with missing lines	Patch %	Lines
src/encoding.rs	0.00%	11 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           develop     #274      +/-   ##
===========================================
- Coverage    56.97%   56.93%   -0.04%     
===========================================
  Files           82       82              
  Lines        15851    15861      +10     
===========================================
  Hits          9031     9031              
- Misses        6820     6830      +10     

Files with missing lines	Coverage Δ
src/encoding.rs	61.97% <0.00%> (-2.27%)	⬇️