Enable Keeper internal async replication by default

[antonio2368]

Changelog category (leave one):

• Backward Incompatible Change

Changelog entry (a user-readable short description of the changes that goes into CHANGELOG.md):

Enable async mode for Keeper's internal replication. Keeper will preserve the same behavior as before with possible performance improvements.
If you are updating from a version older than 23.9, you need to either update first to 23.9+ and than to 25.10+.
You can also set keeper_server.coordination_settings.async_replication to 0 before update and enable it after update is done.

Documentation entry for user-facing changes

• Documentation is written (mandatory for new features)

[clickhouse-gh]

Workflow [PR], commit [adb209d]

Summary: ❌

job_name	test_name	status	info	comment
Performance Comparison (amd_release, master_head, 3/3)		failure
	Configure	failure

[Algunenano]

I understand this is a breaking change. Can we change the category and mention in which version it was introduced (AFAICT 23.9 in #53049), so as to alert people to upgrade to an intermediate version and tell people how to disable the setting just in case, please?