CR: remove unused font

SignalMessaging/categories/UIFont+OWS.h

@@ -31,7 +31,6 @@ NS_ASSUME_NONNULL_BEGIN
 @property (class, readonly, nonatomic) UIFont *ows_dynamicTypeTitle3Font;
 @property (class, readonly, nonatomic) UIFont *ows_dynamicTypeHeadlineFont;
 @property (class, readonly, nonatomic) UIFont *ows_dynamicTypeBodyFont;
-@property (class, readonly, nonatomic) UIFont *ows_dynamicTypeCalloutFont;
 @property (class, readonly, nonatomic) UIFont *ows_dynamicTypeSubheadlineFont;
 @property (class, readonly, nonatomic) UIFont *ows_dynamicTypeFootnoteFont;
 @property (class, readonly, nonatomic) UIFont *ows_dynamicTypeCaption1Font;

SignalMessaging/categories/UIFont+OWS.m

@@ -77,11 +77,6 @@ NS_ASSUME_NONNULL_BEGIN
     return [UIFont preferredFontForTextStyle:UIFontTextStyleBody];
 }
 
-+ (UIFont *)ows_dynamicTypeCalloutFont
-{
-    return [UIFont preferredFontForTextStyle:UIFontTextStyleCallout];
-}
-
 + (UIFont *)ows_dynamicTypeSubheadlineFont
 {
     return [UIFont preferredFontForTextStyle:UIFontTextStyleSubheadline];