minor #57901 Code style change in `@PER-CS2.0 affecting @Symfony` (parentheses for anonymous classes) (bonroyage)

This PR was squashed before being merged into the 7.2 branch.

Discussion
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Code style change in ``@PER`-CS2.0` affecting ``@Symfony`` (parentheses for anonymous classes)

| Q             | A
| ------------- | ---
| Branch?       | 7.2
| Bug fix?      | no
| New feature?  | no
| Deprecations? | no
| Issues        | -
| License       | MIT

I have created a PR (PHP-CS-Fixer/PHP-CS-Fixer#8140) in the PHP-CS-Fixer repo to bring the ``@PER`-CS2.0` ruleset in line with the specifications on the `new_with_parentheses` rule for anonymous classes. Since the ``@Symfony`` ruleset builds upon the ``@PER`-CS2.0` ruleset, they would like confirmation that the Symfony community is OK with this change affecting the Symfony ruleset as well. Should it not be, I'll push another commit there ensuring that the change does not affect ``@Symfony``.

Therefore, this PR is not meant to be merged, but function as an RFC to get your opinion and show the effect it would have when applied to the Symfony source.

Commits
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506e0dd327 Code style change in ``@PER`-CS2.0` affecting ``@Symfony`` (parentheses for anonymous classes)

Author: derrabus

Tests/MailerTest.php

@@ -41,7 +41,7 @@ public function testSendingRawMessages()
 
     public function testSendMessageToBus()
     {
-        $bus = new class() implements MessageBusInterface {
+        $bus = new class implements MessageBusInterface {
             public array $messages = [];
             public array $stamps = [];