[ML] Data Frame Analytics/Anomaly Detection: Custom URLs - entity dro…

…pdown reflects Data View update (#155096)

## Summary

Related meta issue: #150375

This PR ensures that when data view is changed, the query entity
dropdown values update to reflect the fields for the newly chosen data
view. This makes it easier for example to build a link to Discover to
view documents in a data view which contains useful contextual data, and
has fields of the same name as those used in the job but which was not
used to create the job e.g. data views which share a common `host.name`
field.

<img width="448" alt="image"
src="https://user-images.githubusercontent.com/7405507/233050903-d423ab1f-b5c7-479e-98a8-c49761eebe3d.png">


### Checklist

- [x] [Unit or functional
tests](https://www.elastic.co/guide/en/kibana/master/development-tests.html)
were updated or added to match the most common scenarios

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Co-authored-by: Kibana Machine <42973632+kibanamachine@users.noreply.github.com>