fix(artifacts): respect path_prefix when downloading with core

[moredatarequired]

Description

• Fixes WB-18778

• pass path_prefix through to the core process

• skip enqueueing files for download if they don't match the provided prefix

• I updated CHANGELOG.md, or it's not applicable

Testing

Needs additional integration testing, this should have been caught earlier!

[codecov]

Codecov Report

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

Project coverage is 69.34%. Comparing base (185be79) to head (3e97b50).
Report is 71 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #7640      +/-   ##
==========================================
- Coverage   75.68%   69.34%   -6.35%     
==========================================
  Files         500      500              
  Lines       54029    54030       +1     
==========================================
- Hits        40894    37465    -3429     
- Misses      12726    16167    +3441     
+ Partials      409      398      -11     

Flag	Coverage Δ
func	41.44% <ø> (-0.03%)	⬇️
system	52.05% <0.00%> (-11.29%)	⬇️
unit	56.38% <0.00%> (+0.03%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files	Coverage Δ
wandb/sdk/artifacts/artifact.py	67.48% <ø> (-25.79%)	⬇️
core/pkg/artifacts/downloader.go	0.00% <0.00%> (-77.12%)	⬇️

... and 96 files with indirect coverage changes