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### What changes were proposed in this pull request?
SparkML writer gets hadoop conf from session state, instead of the spark context.
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### Why are the changes needed?
Allow for multiple sessions in the same context that have different hadoop configurations.
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### Does this PR introduce any user-facing change?
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No
### How was this patch tested?
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Tested in pyspark.ml.tests.test_persistence.PersistenceTest test_default_read_write
Closes#25505 from helenyugithub/SPARK-28776.
Authored-by: heleny <heleny@palantir.com>
Signed-off-by: Sean Owen <sean.owen@databricks.com>
fb1f868d4f