FINERACT-2494: Add unit tests for ApiParameterHelper in fineract-core

[Ambika-Sony]

Description

This PR adds unit test coverage for the ApiParameterHelper utility class in the fineract-core module.

Changes:

Added ApiParameterHelperTest.java to test core methods like extractFieldsForResponseIfProvided.

Verified code formatting using ./gradlew spotlessApply.

Testing:

Successfully ran locally using: ./gradlew :fineract-core:test --tests "org.apache.fineract.infrastructure.core.api.ApiParameterHelperTest"

All tests passed (100% success rate).

Checklist

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• [ x] Create/update unit or integration tests for verifying the changes made.
• [ x] Follow our coding conventions.
• Add required Swagger annotation and update API documentation at fineract-provider/src/main/resources/static/legacy-docs/apiLive.htm with details of any API changes
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[adamsaghy]

@Ambika-Sony Testing 1 method does not provide too much value. Would you consider to test the whole class?

[Ambika-Sony]

@Ambika-Sony Testing 1 method does not provide too much value. Would you consider to test the whole class?

I've Implemented pagination (limit, offset), sorting (orderBy, sortOrder), and association helpers in ApiParameterHelper.

Added 10 unit tests in ApiParameterHelperTest, covering standard scenarios, null/empty inputs, and defensive checks for whitespace handling.

Verified the build locally with ./gradlew :fineract-core:test --tests ApiParameterHelperTest (all 10 passed).

Looking forward to your feedback.

[Ambika-Sony]

@adamsaghy I noticed the Cucumber E2E tests are failing in the CI, but since my changes are strictly limited to the ApiParameterHelper utility and its unit tests (2 files), these failures seem unrelated to my code. I saw your recent email about the E2E framework transition—perhaps these are known issues?