feat: add IsOptedOutOfScp getter to Player class

EXILED/Exiled.API/Features/Player.cs

@@ -676,6 +676,11 @@
         /// </summary>
         public bool IsScp => Role?.Type.IsScp() ?? false;
 
+        /// <summary>
+        /// Gets a value indicating whether the player has enabled the "Opt out of SCP" setting, which prevents them from being assigned any SCP role.
+        /// 
+        public bool IsOptedOutOfScp => ScpPlayerPicker.IsOptedOutOfScp(ReferenceHub);
+
         /// <summary>
         /// Gets a value indicating whether the player's <see cref="RoleTypeId"/> is any human rank.
         /// </summary>