runelite-api: add method for getting number of friends

runelite-api/src/main/java/net/runelite/api/Client.java

@@ -1020,6 +1020,13 @@ public interface Client extends GameEngine
 	 */
 	Friend[] getFriends();
 
+	/**
+	 * Gets the number of friends on the friends list.
+	 *
+	 * @return
+	 */
+	int getFriendsCount();
+
 	/**
 	 * Checks whether a player is in the same clan chat.
 	 *

runelite-mixins/src/main/java/net/runelite/mixins/RSClientMixin.java

@@ -685,6 +685,25 @@ public abstract class RSClientMixin implements RSClient
 		return (Friend[]) nameables;
 	}
 
+	@Inject
+	@Override
+	public int getFriendsCount()
+	{
+		final RSFriendManager friendManager = getFriendManager();
+		if (friendManager == null)
+		{
+			return -1;
+		}
+
+		final RSFriendContainer friendContainer = friendManager.getFriendContainer();
+		if (friendContainer == null)
+		{
+			return -1;
+		}
+
+		return friendContainer.getCount();
+	}
+
 	@Inject
 	@Override
 	public boolean isClanMember(String name)