test: add download with dfget e2e test for API v2(Rust Client)

[gaius-qi]

Description

Related Issue

dragonflyoss/client#398

Motivation and Context

Screenshots (if appropriate)

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation Update (if none of the other choices apply)

Checklist

• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 51.98%. Comparing base (11ff4d4) to head (20f9cce).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3205      +/-   ##
==========================================
- Coverage   52.04%   51.98%   -0.07%     
==========================================
  Files         173      173              
  Lines       19382    19382              
==========================================
- Hits        10087    10075      -12     
- Misses       8587     8600      +13     
+ Partials      708      707       -1     

Flag	Coverage Δ
unittests	51.98% <ø> (-0.07%)	⬇️

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

see 4 files with indirect coverage changes