fix: fix PySparkProcessor __init__ params type

[andre-marcos-perez]

Issue #, if available:

Description of changes: In the sagemaker.spark.processing module, the PySparkProcessor object constructor params instance_type and instance_count params have wrong typing:

• instance_type is a str but is being typed as int;
• instance_count is an int but is being typed as str.

Testing done:

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