test(integ): keep the shared Spark test jar after the pipeline test

The `build_jar` fixture in the workflow processing tests deleted `hello-spark-java.jar` at teardown. Under xdist, `test_sagemaker_pyspark_v3` in another worker then failed with `code .../hello-spark-java.jar wasn't found` in 2 of the last 3 `integ-tests` jobs. The two modules build the jar in place, so the teardown is not necessary.

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X-AI-Prompt: Can you make the integ tests pass in the pull request hook?
X-AI-Tool: claude-code

Author: evakravi

tests/integ/sagemaker/workflow/test_processing_steps.py

@@ -176,9 +176,6 @@ def build_jar():
             ".",
         ]
     )
-    yield
-    subprocess.run(["rm", os.path.join(jar_file_path, "hello-spark-java.jar")])
-    subprocess.run(["rm", os.path.join(jar_file_path, java_file_path, "HelloJavaSparkApp.class")])
 
 
 @pytest.fixture