Connection leak due to error reconnect

[jkaflik]

Describe the bug

Versions
Grafana v9.2.6
ClickHouse datasource 2.0.4

Query
query agnostic issue. In fact, any invalid query leads us to this issue.

To Reproduce
Navigate to "Explore" and run a query that will fail and repeat this. (SELECT 1=1 FROM missing_table)
Meanwhile, see active connections metric growing (TCP in my case) with each failed query:

SELECT * FROM system.metrics WHERE metric = 'TCPConnection'

Shorthand URL: query

This is due grafana/sqlds does reconnect on any error, not followed with close on released connection.

Expected behavior
The connection is properly closed.