Update Open Sans font files (#14336)

Fix inconsistent rendering between Valo’s bundled Open Sans vs. Google
Fonts provided Open Sans versions on Windows (DirectWrite).

The previous bundled font was generated with Font Squirrel Webfont
Generator with some additional optimizations on (the “Fix GASP Table”
option most likely), which caused the inconsistencies. The new version
is converted with the basic options (most straightforward conversion).

Change-Id: Id9190dc6ceff26d771ec4622a5750b2a1f234304