Show last line of text in editor when guider present

When the guider text is present in the editor (the one explaining what
the Continue button does), the bottom bar is taller and covers the last
line in the textarea.

Leaving some more margin there in case the guider text is two lines long
in other languages.

Change-Id: I229149836c02cbc3cb0cbd84913a5957dc425683
Merge "Show last line of text in editor when guider present"