Update workflow: Make 1.46 PHPUnit non-experimental

from miraheze/.github (miraheze/.github@92c5732)

Author: Universal-Omega

.github/workflows/mediawiki-tests.yml

@@ -29,7 +29,7 @@ jobs:
             composer-test: false
             coverage: false
             experimental-phan: true
-            experimental-phpunit: true
+            experimental-phpunit: false
 
           # Latest MediaWiki master - PHP 8.4
           - mw: 'master'