Fix Python GI API version warning in Wikipedia
Fix Python GI API version warning in Wikipedia

The Wikipedia activity imports from sugar3.graphics.icon without any
other use of GTK+, causing a version warning.

quozl/sugar-toolkit-gtk3,sugarlabs/sugar-toolkit-gtk3,quozl/sugar-toolkit-gtk3,quozl/sugar-toolkit-gtk3,sugarlabs/sugar-toolkit-gtk3,quozl/sugar-toolkit-gtk3,sugarlabs/sugar-toolkit-gtk3