Fix JobParameter validation bug in compact constructor

[KMGeon]

Summary

Fixed validation bug in JobParameter compact constructor that validated value parameter twice instead of validating both name and value parameters.

Fixes gh-5049

Problem Description

The compact constructor in JobParameter.java had a typo:

// Before (Bug)
Assert.notNull(value, "name must not be null");  // ❌ validates 'value' but message says 'name'
Assert.notNull(value, "value must not be null"); // ❌ validates 'value' twice

This allowed creating JobParameter objects with null name, which could cause:

• NullPointerException in equals() and hashCode() methods
• Contract violation (name should never be null)
• Misleading error messages

Changes Made

File: org.springframework.batch.core.job.parameters.JobParameter

• Changed to validate name instead of value

// After (Fixed)
Assert.notNull(name, "name must not be null");   // ✅ now validates 'name'
Assert.notNull(value, "value must not be null"); // ✅ validates 'value'

Testing

• Added new test case for validation
• All existing tests pass
• Code formatting applied (spring-javaformat:apply)
• Full build completed successfully