Fix advection velocity for packing

[LasNikas]

No description provided.

[LasNikas]

/run-gpu-tests

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 2 lines in your changes missing coverage. Please review.

Project coverage is 70.43%. Comparing base (9c2711c) to head (9a7e488).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
src/preprocessing/particle_packing/system.jl	0.00%	2 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #835   +/-   ##
=======================================
  Coverage   70.43%   70.43%           
=======================================
  Files         106      106           
  Lines        6867     6867           
=======================================
  Hits         4837     4837           
  Misses       2030     2030           

Flag	Coverage Δ
unit	70.43% <0.00%> (ø)

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