Bug 31553: Ensure news item content field is always editable

Bug 31553: Ensure news item content field is always editable

Set a padding at the bottom of the news item editor body.

This is a tricky bug to replicate.

Test plan:
1. Set 'AdditionalContentsEditor' syspref = 'a WYSIWYG editor
(TinyMCE)'.

2. Select multiple languages in the 'OPACLanguages' system preference.

3. Go to: Tools > News.

4. Create a new news item. Switch between the different language tabs.

5. Confirm you can always input into the content field in all languages.

6. Edit an exiting news item. Switch between different language tabs.

7. Confirm you can always input into the content field in all languages.

Sponsored-by: Toi Ohomai Institute of Technology, New Zealand
Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>