Integration Test For Multiple Downloads

[PujaDeshmukh17]

This PR will add integration tests for download of multipe attachments scenarios.

Any documentation
https://wiki.one.int.sap/wiki/spaces/sapecm/pages/4701919035/Test+Cases+for+CAP+Java#TestCasesforCAPJava-Supportfordownloadofmultipleattachments:~:text=20.-,Support%20for%20download%20of%20multiple%20attachments,-S%20No.

Integration Jobs:

1. Multi tenant: https://github.com/cap-java/sdm/actions/runs/26808314208
2. Single tenant: https://github.com/cap-java/sdm/actions/runs/26808327104

Type of change

Please delete options that are not relevant.

• Integration Tests

Checklist before requesting a review

• I follow Java Development Guidelines for SAP
• I have tested the functionality on my cloud environment.
• I have provided sufficient automated/ unit tests for the code.
• I have increased or maintained the test coverage.
• I have ran integration tests on my cloud environment.
• I have validated blackduck portal for any vulnerability after my commit.

Upload Screenshots/lists of the scenarios tested

• I have Uploaded Screenshots or added lists of the scenarios tested in description