Remove doctrine/dbal dependency

As per the update guide [1], Doctrine DBAL related classes and methods have been removed.

Remove `doctrine/dbal` as we currently don't use it in the Platform API.

```
docker run --rm -it -v $PWD:/app -u $(id -u):$(id -g) composer:2.9.2 --ignore-platform-req=ext-pcntl remove doctrine/dbal
```

[1]: https://laravel.com/docs/11.x/upgrade#doctrine-dbal-removal

Bug: T426075

Author: outdooracorn

composer.json

@@ -9,7 +9,6 @@
     "type": "project",
     "require": {
         "absszero/laravel-stackdriver-error-reporting": "^1.9",
-        "doctrine/dbal": "^3.1",
         "firebase/php-jwt": "^7.0",
         "google/recaptcha": "^1.2",
         "guzzlehttp/guzzle": "^7.8",