Expected behavior

Content shouldn't be lost even if the system chooses to kill the Editor Activity while it's open but in the background

Actual behavior

if Don't keep activities is turned ON, and you open the Gutenberg editor and type something in it, then send the app to the background and bring it back to the foreground, the editor appears empty (the content is not saved / re-populated).

Steps to reproduce the behavior

1. set Don't keep activities ON and choose to use Gutenberg in App Settings within WPAndroid/Me tab.
2. start a new draft
3. type something
4. send the app to the background (i.e. tap the HOME button of the device)
5. bring it back to the foreground
6. observe the Editor shows empty now

Tested on [Google Pixel], Android [8.1]