Support Clickhouse varchar comparison pushdown

[ssheikin]

Description

Additional context and related issues

• More predicate pushdown in ClickHouse connector #7100
• Running branch for Clickhouse pushdowns #23460
• Improve Clickhouse pushdown. Attempt 1 #22921
• Test predicates pushdown to ClickHouse FLOAT type #23496
• Unconditionally pushdown varchar predicate to Clickhouse #23516
• Improve Clickhouse varchar equalities pushdown #23455
• Support Clickhouse varchar comparison pushdown #23558
• Improve IS NULL pushdown for ClickHouse complex expression #23459

Release notes

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# Clickhouse
* Improve varchar comparison pushdown for complex expression ({issue}`23558`)

[Praveen2112]

Can we move this to a dedicated test for enums ?

[ssheikin]

It was initially implemented as a dedicated test, however it is duplicated in this test anyway to support:

            assertThat(query("SELECT some_column FROM " + table.getName() + " WHERE a_string = a_string_alias")).isFullyPushedDown();
            assertThat(query("SELECT some_column FROM " + table.getName() + " WHERE a_string = a_string_alias" + withConnectorExpression)).isFullyPushedDown();
            assertThat(query("SELECT some_column FROM " + table.getName() + " WHERE a_string = a_enum_1")).isNotFullyPushedDown(FilterNode.class);
            assertThat(query("SELECT some_column FROM " + table.getName() + " WHERE a_string = a_enum_1" + withConnectorExpression)).isNotFullyPushedDown(FilterNode.class);

scenarios. So let it be as it is.

[ssheikin]

@Praveen2112 please approve

[Praveen2112]

LGTM % changes on method name and additional test coverage for a few data types.

[ssheikin]

@Praveen2112 all comments are addressed.

[Praveen2112]

Thanks for working on this.

[Praveen2112]

@hashhar / @ebyhr Do you want to take another round of review for this PR.