Change the favicon monogram font for suggested articles

This CL changes the font of the fallback monogram of the favicons of suggested
articles, making it bigger and medium instead of regular.

BUG=none

Review-Url: https://codereview.chromium.org/2801323002
Cr-Commit-Position: refs/heads/master@{#462873}

ios/chrome/browser/ui/content_suggestions/cells/content_suggestions_article_item.mm

@@ -173,8 +173,7 @@ const CGFloat kAnimationDuration = 0.3;
     _titleLabel.font = [MDCTypography subheadFont];
     _subtitleLabel.font = [MDCTypography body1Font];
     _publisherLabel.font = [MDCTypography captionFont];
-    _faviconView.font =
-        [[MDCTypography fontLoader] regularFontOfSize:kFaviconSize / 2];
+    _faviconView.font = [[MDCTypography fontLoader] mediumFontOfSize:10];
 
     _subtitleLabel.textColor = [[MDCPalette greyPalette] tint700];
     _publisherLabel.textColor = [[MDCPalette greyPalette] tint700];