Docs: Fix missing documentation in Media and Plugin Install list tables

[noruzzamans]

Trac Ticket: https://core.trac.wordpress.org/ticket/64224

Why this change?

This aligns the codebase with the WordPress PHP Documentation Standards, ensuring that global variables used within functions are properly documented for better static analysis and code clarity.

Missing Tags: Added missing @global, @param, and @return descriptions.
Method Summaries: Added summaries for several methods in both list table classes that were previously undocumented.
Property Docs: Added DocBlocks for class properties ($order, $orderby, etc.).

[github-actions]

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Props noruzzaman, huzaifaalmesbah, westonruter.

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[github-actions]

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[westonruter]

array for the return value and the $tabs should be fleshed out

[noruzzamans]

Thanks for the feedback! I have fleshed out the types for $tabs and the return value

[westonruter]

This seems to be reducing information? Granted, it is returning an empty array.

[noruzzamans]

My apologies for the oversight. I have updated the doc blocks and restored the missing info.