[Response Ops][Task Manager] Deprecating `xpack.task_manager.claim_st…

…rategy` config (#203341)

Resolves #202492

## Summary

For 9.0 only. Deprecates `xpack.task_manager.claim_strategy`
configuration. Logs warning if value is explicitly set. This value was
never added to the Kibana docs in
`docs/settings/task-manager-settings.asciidoc` so nothing to remove
there.

## To Verify

Set `xpack.task_manager.claim_strategy` config in `kibana.dev.yml` and
start Kibana. See warning get logged.

Co-authored-by: Elastic Machine <elasticmachine@users.noreply.github.com>

x-pack/plugins/task_manager/server/index.ts

@@ -69,6 +69,10 @@ export const config: PluginConfigDescriptor<TaskManagerConfig> = {
         level: 'warning',
         message: `Configuring "xpack.task_manager.max_workers" is deprecated and will be removed in a future version. Remove this setting and use "xpack.task_manager.capacity" instead.`,
       }),
+      deprecate('claim_strategy', 'a future version', {
+        level: 'warning',
+        message: `Configuring "xpack.task_manager.claim_strategy" is deprecated and will be removed in a future version. This setting should be removed.`,
+      }),
       (settings, fromPath, addDeprecation) => {
         const taskManager = get(settings, fromPath);
         if (taskManager?.index) {