MINOR: Use explicit AcknowledgeType enums in SharePartitionTest (#20802)

This PR updates the `SharePartitionTest.java` unit tests to use
`AcknowledgeType` enums instead of hardcoded byte values. This makes the
tests more readable and maintainable, and ensures that acknowledgement
types are referenced consistently throughout the codebase.

Reviewers: Andrew Schofield <[email protected]>

Author: JimmyWang6