[12.x] Pass LoggerInterface when constructing RoundrobinTransport instance

[jnoordsij]

As a follow-up to symfony/symfony#60110 which introduces an additional constructor property logger to the RoundRobinTransport class, this PR ensures the app-bound LoggerInterface will be passed when constructing such a class.

Note that this will require Symfony 7.4.0 or higher, which is due for release in November 2025. Given that passing additional parameters to constructors is allowed in PHP (they are just silently ignored), this PR as such is both backwards and forwards compatible, however at current would do effectively nothing. If therefore it is preferable to keep this as draft until (near) the release of Symfony 7.4, that is also perfectly fine with me.

I've already tested to ensure tests still pass with the following composer.json patch:

         "symfony/finder": "^7.2.0",
         "symfony/http-foundation": "^7.2.0",
         "symfony/http-kernel": "^7.2.0",
-        "symfony/mailer": "^7.2.0",
+        "symfony/mailer": "7.4.x-dev as 7.4.0",
         "symfony/mime": "^7.2.0",
         "symfony/polyfill-php83": "^1.31",
         "symfony/process": "^7.2.0",

[jnoordsij]

As static analysis (logically) fails I'll go ahead and keep this in draft until November.