Update InfrahubNode artifact_fetch and artifact_generate methods to use artiface name instead of the defintion name

[wvandeun]

Now that artifacts are properly getting their name from the artifact_name attribute of the artifact definition (opsmill/infrahub#5484), we need to update the InfrahubNode artifact_fetch and artifact_generate method to use the name of the artifact instead.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

@@           Coverage Diff           @@
##           stable     #266   +/-   ##
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  Coverage   70.36%   70.36%           
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  Files          82       82           
  Lines        7497     7497           
  Branches     1389     1389           
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  Hits         5275     5275           
  Misses       1848     1848           
  Partials      374      374           

Flag	Coverage Δ
integration-tests	22.46% <0.00%> (ø)
python-3.10	45.56% <100.00%> (ø)
python-3.11	45.56% <100.00%> (ø)
python-3.12	45.56% <100.00%> (ø)
python-3.13	45.56% <100.00%> (ø)
python-3.9	45.56% <100.00%> (ø)
python-filler-3.12	23.96% <0.00%> (ø)

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Files with missing lines	Coverage Δ
infrahub_sdk/node.py	77.58% <100.00%> (ø)