Use null coalescing operator instead of isset() ternaries

[Soean]

Trac ticket: https://core.trac.wordpress.org/ticket/63430

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[github-actions]

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[github-actions]

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[westonruter]

@Soean Thanks for catching these. I believe the changes to wp-content/themes need to be reverted, however. Themes need to be compatible with older versions of PHP. For example, Twenty Twenty-One is requires PHP 5.6 which does not support the null coalescing operator (as it was added in PHP 7.0).

[Copilot]

Pull request overview

This PR modernizes PHP code by replacing verbose isset() ternary expressions with the more concise null coalescing operator (??). This is a code quality improvement that makes the codebase more readable while maintaining identical behavior.

Changes:

• Replaced isset() ternary patterns with the null coalescing operator (??) in 5 files
• Changes are limited to cases where values are extracted directly without additional function calls

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
src/wp-includes/post-formats.php	Simplified array access with null coalescing for post format string lookup
src/wp-includes/functions.php	Simplified array access with null coalescing for image MIME type extraction
src/wp-includes/class-wp-xmlrpc-server.php	Simplified array access with null coalescing for MIME type parameter in media library function
src/wp-admin/network/edit.php	Simplified superglobal access with null coalescing for action parameter
src/wp-admin/includes/class-wp-comments-list-table.php	Simplified multiple superglobal accesses with null coalescing for search, user_id, orderby, and order parameters

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