Lens only shows keyword fields, not text fields

[jportner]

Kibana version: Verified in 7.11.1, 7.12.0, 7.13.0-SNAPSHOT, and master

Describe the bug: Lens only shows keyword fields, not text fields

Steps to reproduce:

1. Create a test document in Dev Tools:

   POST test/_doc
   {
     "link": "https://www.example.com"
   }
   

2. Create an Index Pattern for this document:
   
3. Create a Lens Visualization:
   

Expected behavior: Lens should show both link and link.keyword in the available fields

[elasticmachine]

Pinging @elastic/kibana-app (Team:KibanaApp)

[wylieconlon]

@jportner these are hidden from Lens because we currently don't allow you to visualize the full-text fields. We might be able to display them in a Data Table visualization in the future.

[timductive]

Closing this as text fields in a datatable are supported in ESQL along with aggregations.