[Alerting] enable event log index by default

[pmuellr]

Currently the event log is configured to not index event documents, by default, via the indexEntries config key:

kibana/x-pack/plugins/event_log/server/types.ts

Lines 13 to 17 in 300df64

	export const ConfigSchema = schema.object({
	enabled: schema.boolean({ defaultValue: true }),
	logEntries: schema.boolean({ defaultValue: false }),
	indexEntries: schema.boolean({ defaultValue: false }),
	});

It's time to change it to change the default to true!

I think we'll leave the existing config key in, as a safety valve, so we can have devs disable in their dev config if something goes bad, but long-term we might want to just remove it. Something to think about for the future anyway.

[elasticmachine]

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