[alerting event log] change ES access functions to use callCluster types

[pmuellr]

Currently all the ES calls made by event log are done via a single function:

kibana/x-pack/plugins/event_log/server/es/context.ts

Lines 76 to 89 in 31c2a89

	async callEs(operation: string, body?: any): Promise<any> {
	try {
	this.debug(`callEs(${operation}) calls:`, body);
	const result = await this.clusterClient.callAsInternalUser(operation, body);
	this.debug(`callEs(${operation}) result:`, result);
	return result;
	} catch (err) {
	this.debug(`callEs(${operation}) error:`, {
	message: err.message,
	statusCode: err.statusCode,
	});
	throw err;
	}
	}

This function is largely not needed in this form, it was useful during initial development to debug the calls to ES, but we can use debug logging where needed, instead.

The originating request for this came from a PR comment indicating we weren't making use of the existing callCluster type signatures. So, we'll get that back if we just start calling it directly.

Given the number of calls we are likely to have (few), we could also just write wrappers for the ones that we need ...

[elasticmachine]

Pinging @elastic/kibana-alerting-services (Team:Alerting Services)

[YulNaumenko]

@pmuellr I don't think this issue is relevant since we migrated to the new ES client and don't use callCluster

[pmuellr]

@YulNaumenko Ya, you're right, so closing. Thx!