fix: Some bad math with the JitterBuffer sequence tracking

[thatsnotright]

Description

I'm not sure what I was thinking, uint16 should wrap itself correctly.

Reference issue

Fixes #253

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 72.45%. Comparing base (142f17f) to head (9814d5f).

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #254      +/-   ##
==========================================
+ Coverage   72.39%   72.45%   +0.05%     
==========================================
  Files          79       79              
  Lines        3648     3648              
==========================================
+ Hits         2641     2643       +2     
+ Misses        870      869       -1     
+ Partials      137      136       -1     

Flag	Coverage Δ
go	72.45% <100.00%> (+0.05%)	:arrow_up:
wasm	70.55% <100.00%> (ø)

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[thatsnotright]

@Sean-Der Can you let me know if this PR is good to go? Thanks!