Update clickhouse.mdx (apache#17937)

There is a contradiction on this page - the requirements show `clickhouse-sqlalchemy` and then there is this sentence stating that the recommended connector is `sqlalchemy-clickhouse`, which is somewhat of an abandoned driver that is not seeing any activity in Github. I would suggest either removing the sentence about "recommended connector" or changing the link (as I have done in this PR).

docs/src/pages/docs/Connecting to Databases/clickhouse.mdx

@@ -23,7 +23,7 @@ clickhouse-sqlalchemy>=0.1.6
 ```
 
 The recommended connector library for Clickhouse is
-[sqlalchemy-clickhouse](https://github.com/cloudflare/sqlalchemy-clickhouse).
+[clickhouse-sqlalchemy](https://github.com/xzkostyan/clickhouse-sqlalchemy).
 
 The expected connection string is formatted as follows: