Python: Fix kernel parameter metadata input type arg to call type_

[moonbox3]

Motivation and Context

To address a typing issue, we updated the kernel parameter metadata so that the input type argument now calls type (configured as an alias) rather than the model’s parameter type_. Previously, setting the alias did not update the underlying type_ attribute, leaving it as None. As a result, when generating the JSON schema, the parameter_type was omitted, causing some customers who sent KernelFunctionMetadata to the OpenAI model to receive a 400 error due to a malformed schema.

Description

Revert the change and add a unit test to make sure we check for the expected schema.

Contribution Checklist

• The code builds clean without any errors or warnings
• The PR follows the SK Contribution Guidelines and the pre-submission formatting script raises no violations
• All unit tests pass, and I have added new tests where possible
• I didn't break anyone 😄

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