tests: fix lora tests handling

[dtrifiro]

tests were being skipped because of the way fixtures were being used

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 41.66667% with 7 lines in your changes missing coverage. Please review.

Project coverage is 62.89%. Comparing base (0b69d69) to head (44cc033).

Files	Patch %	Lines
tests/conftest.py	41.66%	5 Missing and 2 partials ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##             main      #51       +/-   ##
===========================================
+ Coverage   31.45%   62.89%   +31.43%     
===========================================
  Files          18       18               
  Lines        1278     1280        +2     
  Branches      228      228               
===========================================
+ Hits          402      805      +403     
+ Misses        874      398      -476     
- Partials        2       77       +75     

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[dtrifiro]

Tests were failing because CI expects the cpu version to be installed, but opendatahub-io/vllm#95 changed the odh vllm package name to vllm-odh, causing the upstream vllm to be installed.

This was reverted in opendatahub-io/vllm#98.