Refactor lightning_gpu_utils unit tests to remove the dependency on statevector class

[multiphaseCFD]

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Context:

Refactor lightning_gpu_utils unit tests

Description of the Change:

Unit tests for sparseMV and sparseMVMPI relied on the DataBuffer class instead ofStateVectorCudaManaged and StateVectorCudaManagedMPI.

Benefits:

It will make the lightning_gpu_utils an independent module, which can be used for both cutensornet and custatevec backends after moving it to /src/utils/.

Possible Drawbacks:

Related GitHub Issues:

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 99.10%. Comparing base (c6a8260) to head (f4b611e).

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #675      +/-   ##
==========================================
+ Coverage   98.99%   99.10%   +0.10%     
==========================================
  Files         173      207      +34     
  Lines       24399    29804    +5405     
==========================================
+ Hits        24155    29537    +5382     
- Misses        244      267      +23     

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[vincentmr]

Looks good to me @multiphaseCFD ! Don't forget to add the ci::build_wheels label before merging.

[maliasadi]

🙌