Fix create and import document forms not submitting when pressing Enter

For LTS 2016 (8.10) I'm able to submit the create and import forms by pressing the enter key. On LTS 2017 (9.10) and 10.2-SNAPSHOT, it doesn't work.

Steps to reproduce (create form):
1. In a workspace, click the "Add Content" icon on the bottom right.
2. Select the "FILE" type.
3. Click on the "Title" field and press the enter key. The correct behaviour would be to trigger the form validation (just like it's done by clicking the "CREATE" button).

Steps to reproduce (import form):
1. In a workspace, click the "Add Content" icon on the bottom right.
2. Select the "IMPORT" tab.
3. Drag and drop any PDF file (e.g. this one).
4. Click "ADD PROPERTIES".
5. On the "Type" dropdown, select "File".
6. Click on the "Title" field and press the enter key. The correct behaviour would be to trigger the form validation (just like it's done by clicking the "CREATE" button).