[Maps] remove geo field check for index pattern select

[nreese]

When selecting an index pattern while adding a map layer or creating a geo alert, the index pattern list is filtered to only show index patterns with geo_point and/or geo_shape fields. This has been problematic and is the source of several bugs like #95418.

The problem is that fields are not stored with index pattern saved objects. Fields are loaded via a separate API call so checking the fields for lots of index patterns will cause the index pattern select to be sluggish.

I recommend just removing the geo field check altogether and allow the index pattern select to show all index patterns. Then, when the user selects an index pattern, do the field check and display an error message if the index pattern does not contain the expected geo field type. One benefit of this solution is that with the addition of runtime fields, this solution would provide a way to notify users that the index pattern does not have a geo field and give them an action to add a geo_point or geo_shape field to the index pattern via runtime fields.

Thoughts?

[elasticmachine]

Pinging @elastic/kibana-gis (Team:Geo)

[kmartastic]

You make a great point.

• What if a user had an index with latitude and longitude fields? (via runtime field)
• What if a user has an index with administrative names (and we support geocoding in the future)?

Removing this check, gives the user a more flexible flow (needed in the future).