[Content editor]If a validation error is displayed, the document cannot be saved as draft

Description

**After the Save draft functionality was introduced, the editor could save a document without the validation kicks in. But, if the editor first tries to press Done, then validation kicks in, which also blocks the editor to save the document as draft.

Steps to reproduce:

1. Go to Content perspective

2. Create a new News document

3. Press Done

4. Wait for the validation to kick in, saying that the document has errors

5. Press the Keep draft button

Expected result:

The document is saved as draft.

Actual result:

The editor cannot save the document. 

Workaround:

Cancel the document (the editor will lose the changes to the document).