Add fields column disappears after all fields

[harshit078]

Bug Description

• Currently, when user has selected all fields in a relation then the column to add fields disappears and doesn't allow the user to customize fields unless he hides a field.
• Expected behaviour should be that add fields column should be present at all times and allow users to select customize fields even when selected all fields.

Current Behaviour

[Bonapara]

We can keep the customize field button when there are no more fields to show.

[heypratik]

@Bonapara Please assign this bug to me

[Bonapara]

Thanks for contributing @heypratik