Move most references to PKMember.Name to go through helper extepsions for privacy

PluralKit.Bot/Commands/MemberAvatar.cs

@@ -61,7 +61,7 @@ namespace PluralKit.Bot
             }
 
             var eb = new DiscordEmbedBuilder()
-                .WithTitle($"{target.Name.SanitizeMentions()}'s {field}")
+                .WithTitle($"{target.NameFor(ctx).SanitizeMentions()}'s {field}")
                 .WithImageUrl(currentValue);
             if (target.System == ctx.System?.Id)
                 eb.WithDescription($"To clear, use `pk;member {target.Hid} {cmd} clear`.");