doctrine/dbal v3 - Make sure that values passed to are not null

[scyzoryck]

Hello! My first PR here.
Partially fixes #8884 - 7 out of 117 issues.

Let's start from fixing 2 types of issues:

�[0;31mERROR�[0m: PossiblyNullArgument - lib/Doctrine/ORM/Persisters/Collection/ManyToManyPersister.php:765:66 - Argument 3 of Doctrine\DBAL\Platforms\AbstractPlatform::modifyLimitQuery cannot be null, possibly null value provided (see https://psalm.dev/078)
            return $this->platform->modifyLimitQuery('', $limit, �[97;41m$offset�[0m);

�[0;31mERROR�[0m: PossiblyNullArgument - lib/Doctrine/ORM/Persisters/Entity/JoinedSubclassPersister.php:335:62 - Argument 2 of Doctrine\DBAL\Platforms\AbstractPlatform::appendLockHint cannot be null, possibly null value provided (see https://psalm.dev/078)
        $lock       = $this->platform->appendLockHint($from, �[97;41m$lockMode�[0m);

The first issue is simpler - modifyLimitQuery has default $offset value set to 0 - so let's pass it instead of null.
For AbstractPlatform::appendLockHint there is no default value, so passing LockMode::NONE seems to be the best choice - it would not affect any known implementation.

[greg0ire]

Thanks and congrats on your first PR!