Fixes the broken download button in clinical data tab in study view

[MalavikaS2000]

Resolves #11142

• Fixed the button to get file in tsv format instead of json format.
• Added validations to handle empty arrays.
• Verified that the download button works as expected and generates the right file format.
• Ran all tests to assure nothing else was accidentally broken in the java part by running: mvn integration-test.

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[alisman]

@gblaih can you review and test this PR? thanks! (@MalavikaS2000 thanks for submitting)