Full screen blocks all dialogs

Problem/Motivation

When using the full screen feature with any dialogs they seem to be covered up, example entity embed

Steps to reproduce

Setup a ckeditor instance with entity embed and fullscreen
Create a piece of content
Go full screen
Try and click entity embed button and notice the dialog doesn't appear
Close fullscreen and see it did appear but hidden

Proposed resolution

Don't block dialog from appearing.

Remaining tasks

Agree
Implement
Review

User interface changes

API changes

Data model changes