[Improvement][DataSourcePlugin]tiny optimize of datasource plugin module

[genuinner]

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Description

when I study adding datasource plugin, i find the datasource-special constants like COM_CLICKHOUSE_JDBC_DRIVER = "com.clickhouse.jdbc.ClickHouseDriver" only used in ClickHouseDataSourceProcessor, so i move all related constant to the special DataSourceProcessor, it does not make too much sense, I just think it is a better format and pattern, after that, I can easily setDefaultValidationQuery to fit various datasource, which has problem using the original code.
So you can evaluate if this change is needed.

Are you willing to submit a PR?

• Yes I am willing to submit a PR!

Code of Conduct

• I agree to follow this project's Code of Conduct

[genuinner]

#14540

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This issue has been closed because it has not received response for too long time. You could reopen it if you encountered similar problems in the future.