Do not restart ClickHouse on configuration.zookeeper changes

[identw]

Honor configurationRestartPolicy for zookeeper/* (default no) so endpoint updates apply without hostForceRestart, while other reboot-required changes still restart.

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Summary

isZookeeperChangeRequiresReboot ignored configurationRestartPolicy and always restarted ClickHouse when ZooKeeper endpoints changed, even though the default policy is zookeeper/*: "no". ClickHouse reloads <zookeeper> from config without a process restart.

Test plan

• go test ./pkg/model/ -run TestIsConfigurationChangeRequiresReboot -count=1

[alex-zaitsev]

ClickHouse can apply ZooKeeper config changes without a server restart starting in the 20.10 line.

That landed in three steps:

Version	What became reloadable
20.10	Main <zookeeper> section — dynamic reload (#14678). On this first cut, ReplicatedMergeTree / DDL worker typically picked up the new client after the current ZooKeeper session expired.
20.11	More reliable runtime update of the main ZooKeeper config (#16630).
20.12	<auxiliary_zookeepers> can also be changed in config.xml and reloaded without a restart (#16627).

In practice: any current supported release (21.8 LTS and later) does not need a ClickHouse restart for ZooKeeper / Keeper endpoint or settings changes. The server reloads config.xml / config.d/ itself; SYSTEM RELOAD CONFIG forces it.