Allow localized search indexing to be disabled.

[codyspring]

Expected behaviour

Be able to turn off search indexing for non-default locales.

Actual behaviour

There's no option for this.

Use case

It's a bit specific so I imagine low priority but the searchable things in our indexes aren't localized and when the indexes are updated we spend a lot of unnecessary calls to Algolia putting us closer to the new pricing model's operation limits.