Fix: Render simple arrays inline in What-If output and add unit test

[build-with-shivam]

• This change fixes an issue in the What-If output formatting where arrays of primitive/leaf values were rendered one element per line. Simple arrays are now rendered inline (e.g., [1, 2, 3]) to improve readability.
• Added a unit test to assert the inline formatting behavior.

[build-with-shivam]

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