FINERACT-2537: Add unit tests for StreamResponseUtil

[devi-pathak2263]

Description

This PR adds unit tests for the 'StreamResponseUtil' utility class in 'fineract-core'.

The following scenarios are covered:

• Response generation via 'ok(StreamResponseData)'
• Asynchronous response handling via 'ok(AsyncResponse, StreamResponseData)'
• Behavior when 'dispositionType' is absent or present ('attachment'/'inline')
• Correct generation of 'Content-Disposition' headers
• Verification that 'StreamingOutput' writes the expected stream content

These tests improve code coverage and ensure reliable behavior of response streaming utilities.

JIRA:

https://issues.apache.org/jira/browse/FINERACT-2537

Testing

Executed locally:

• ./gradlew spotlessApply
• ./gradlew :fineract-core:test

Checklist

Please make sure these boxes are checked before submitting your pull request - thanks!

• Write the commit message as per our guidelines
• Acknowledge that we will not review PRs that are not passing the build ("green") - it is your responsibility to get a proposed PR to pass the build, not primarily the project's maintainers.
• Create/update unit or integration tests for verifying the changes made.
• 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
• This PR must not be a "code dump". Large changes can be made in a branch, with assistance. Ask for help on the developer mailing list.

[adamsaghy]

@devi-pathak2263 Can you please:

Set the commit email address to match with your github account email address?
Set GPG signature for commit?

[devi-pathak2263]

@devi-pathak2263 Can you please:

Set the commit email address to match with your github account email address? Set GPG signature for commit?

I have updated the commit author email to match my GitHub account and amended the commit with a GPG signature. I also updated the test imports to follow project conventions.

Please let me know if anything else needs adjustment.

[devi-pathak2263]

Hi team, could someone please approve the workflows for this PR so that CI checks can run? Thanks!

[devi-pathak2263]

Hi team, all checks have passed. Please let me know if any further changes are required. Thanks!