[ML] Job wizard lat_long detector

[benwtrent]

Ever since 7.3 the scripted field work around for lat_long has not been necessary. The lat_long detector can now work on geo_centroid aggs, geo_point and geo_shape fields.

I think it would be nice for the single metric wizard to provide an option for lat_long against the appropriately mapped fields.

Additionally, the adv. wizard should allow lat_long being selected and then choosing an appropriate geo field.

As it stands now, I cannot figure out how to build a lat_long detector in the new wizard. Since I cannot choose the appropriate fields (or reference a scripted field from the datafeed), I have to skip right to the JSON.

[elasticmachine]

Pinging @elastic/ml-ui (:ml)