chore: align package phpunit and paratest versions to ^12 and ^7

Update all Package/*/composer.json and tools/monorepo/composer.json
to use phpunit ^12 and paratest ^7, matching the root composer.json.
This resolves monorepo-builder validate conflicts for the upcoming
BigQuery driver adoption.

Author: zajca

composer.json

@@ -37,7 +37,7 @@
 	},
 	"require-dev": {
 		"ext-curl": "*",
-		"phpunit/phpunit": "^9.0|^10"
+		"phpunit/phpunit": "^12"
 	},
 	"scripts": {
 		"tests": "phpunit --testsuite=unit",