Allow user to add display modes from respective field UI's.

Problem/Motivation

Currently the users cannot add/create a new form/display mode while entity creation flow.The view display mode has a link Manage view modes which redirects to the view display mode form where you can create a new display mode to attach to the entity.We want the to provide the users with the flexibility of adding display modes from the field UI of the entity flow creation.

Steps to reproduce

Proposed resolution

The proposed resolution is that we can directly create both the display modes from respective Field UIs. The current implementation allows a user to create respective display modes by opening the respective forms in a modal on while the user is not redirected anywhere.

Remaining tasks

1. Usability review
2. Accessibility review

User interface changes

API changes

Data model changes

Release notes snippet