…92483)

Resolve: elastic#184088

In this PR add telemetry collection of these metrics:

- total number of MW in deployments
- number of active MW with "repeat" toggle on (time based)
- number of active MW with "filter alerts" toggle on (KQL based)

## Testing

Create several MW with different settings (toggles on and off)
To test changes reflected in telemetry object,
modify this file: `x-pack/plugins/alerting/server/usage/task.ts`

With:

```
async function scheduleTasks(logger: Logger, taskManager: TaskManagerStartContract) {
  try {
    await taskManager.ensureScheduled({
      id: TASK_ID,
      taskType: TELEMETRY_TASK_TYPE,
      state: emptyState,
      params: {},
      schedule: SCHEDULE,
    });
  } catch (e) {
    logger.error(`Error scheduling ${TASK_ID}, received ${e.message}`);
  }
  await taskManager.runSoon(TASK_ID);
}
```

This will cause the telemetry to be sent as soon as the server is
restarted.

**Run Telemetry usage payload API in your browser console to verify
telemetry object:**

https://docs.elastic.dev/telemetry/collection/snapshot-telemetry#telemetry-usage-payload-api
P.S.: Add space at the beginning of URL

### Checklist

- [x] [Unit or functional
tests](https://www.elastic.co/guide/en/kibana/master/development-tests.html)
were updated or added to match the most common scenarios

---------

Co-authored-by: Elastic Machine <elasticmachine@users.noreply.github.com>
(cherry picked from commit eabb102)