[Discover] <FieldIcon/> usage is inconsistent

[Dosant]

Kibana version: Main (8.1)

Describe the bug:

Looks like logic for extracting type from a field for <FieldIcon/> is different in different places in discover.
For example, discover's document table always displays string fields icons as string, but the field list displays an underlying es type (e.g. version or text)

Steps to reproduce:

1. Create a field of type version or text
2. See how it is displayed in Discover in the field list and in the document grid.
3. They are displayed differently

Expected behavior:

They should be displayed in the same manner in different places.

Screenshots (if relevant):

Any additional context:

Noticed in: #123739

[elasticmachine]

Pinging @elastic/kibana-data-discovery (Team:DataDiscovery)

[mbondyra]

Do we know which icon should be used?

[Dosant]

Specifically for the version field, the icon in the left-field list is correct.

I think we need to compare how FieldIcon is used on the left and on the right and make the usage on the right the same as on the left

[drewdaemon]

@mbondyra are you thinking of taking this one?

[mbondyra]

@andrewctate you can take it, I am still working on something else 👌🏼

[kertal]

@elastic/kibana-data-discovery 🍰 for you both, no matter who takes care of it