Adding new monitor template for ClickHouse

[sangeetashivaji]

What does this PR do?

Motivation

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⚠️ Recommendation: Add qa/skip-qa label

This PR does not modify any files shipped with the agent.

To help streamline the release process, please consider adding the qa/skip-qa label if these changes do not require QA testing.

[chatgpt-codex-connector]

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[chatgpt-codex-connector]

Scope these ClickHouse alerts per host

This query creates a single aggregated alert across all hosts (avg:...{*} without by {host}), but the monitor name/message uses {{host.name}} and describes host-level symptoms. In multi-host deployments, one overloaded node can be averaged out by healthy nodes, so the alert may never fire even when a specific host is unhealthy, and the host template variable may be empty in notifications. The same pattern appears in the other newly added query monitors (clickhouse_high_query_failure_rate.json, clickhouse_high_thread_cpu_wait.json, clickhouse_merge_pool_saturation.json, and clickhouse_replica_delay.json).

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