Fix keyboard shortcut display layout

The keyboard_shortcuts_keyword TextView in keyboard_shortcut_app_item
layout was wrap_content making it take all the space in case the text is
too long. The TextView is now rendered indide a KeyboardShortcutsLayout
which extends the RelativeLayout and sets the maxWidth of
keyboard_shortcuts_keyword TextView to 70% when onMeasure is called with
EXACT MeasureSpec.

Bug: 32980732
Fixes: 32980732
Test: Manual
Change-Id: I1250802af0a4ad011e842318384ca6fe5686989c