[Store][ClickHouse] Make store final readonly

[OskarStark]

Q	A
Bug fix?	no
New feature?	yes
Docs?	no
Issues	--
License	MIT

[lyrixx]

Hello, I thinks it's a bad idea to mark it as final.

For exemple, I override the store, to override some parts:

class ClickHouseStore extends SymfonyClickHouseStore
{
    public function initialize(array $options = []): void
    {
        $sql = <<<'SQL'
            CREATE TABLE IF NOT EXISTS {{ table }} (
                id UUID,
                metadata String,
                embedding Array(Float32),
                crawlId UUID,
                -- INDEX embedding_idx embedding TYPE vector_similarity('hnsw', 'cosineDistance', 3072)
            ) ENGINE = MergeTree()
            PRIMARY KEY crawlId
        SQL;

        $this->execute('POST', $sql);
    }

    protected function formatVectorDocument(VectorDocument $document): array
    {
        $formatted = parent::formatVectorDocument($document);

        $formatted['crawlId'] = $document->metadata['crawlId'];

        return $formatted;
    }
}

Composition here is not easy, and seems overkill.

Could we consider to revert this PR?

[OskarStark]

Yes, let's open them up all please, thanks