Align phpcs-sniffs with root composer

[ernilambar]

In this PR:

• Treat root composer.json as the source of truth for dependencies in phpcs-sniffs.
• Resolve PHP 8.2+ failure in phpcs-sniffs tests caused by token-type conflict between PHP_CodeSniffer and nikic/php-parser.

Changes:

• Aligned with root: Same constraints for overlapping packages: php >=7.4, config.platform.php 7.4, wp-coding-standards/wpcs ^3.2.0, slevomat/coding-standard ^8.18, phpunit/phpunit ^9.0, dealerdirect/phpcodesniffer-composer-installer ^1.0.0.
• phpcompatibility: Bumped to ^10.0; set minimum-stability: alpha so 10.0.0-alpha2 can install (root stays on dev-develop due to wp-cli-tests). We could also fix this after new WP-CLI is released.
• Fix: In phpcs-sniffs/Tests/bootstrap.php, load nikic/php-parser’s compatibility_tokens.php before the PHPCS autoloader so token constants are defined as int and PHPCS does not override them.
• Note: This workaround in bootstrap can be removed after minimum PHP and packages are upgraded to versions that resolve the conflict.

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Co-authored-by: ernilambar <nilambar@git.wordpress.org>
Co-authored-by: davidperezgar <davidperez@git.wordpress.org>
Co-authored-by: frantorres <frantorres@git.wordpress.org>

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