Update favicon wiktionary/si.ico

Added 48x48 and 32x32 versions of the icon. I was unable to
find a high resolution version of the original 16x16 icon so
I used the images https://commons.wikimedia.org/wiki/File:WiktionarySi.png
and https://commons.wikimedia.org/wiki/File:Wiktionary_small.svg to
recreate the icon in 48x48 and 32x32 and remake the 16x16 version.

Bug: 58367
Change-Id: I6ce4866e9ea43579f6ddbf5d74a2d736ac92d81c