[Tasks] Update tasks in all zones if invalid zone set (#4550)

This allows task elements to update in any zone when it has an invalid
zone id <= 0. This has the same effect as leaving the zones field empty
except "Unknown Zone" instead of "ALL" will be shown in task windows.

Note that Titanium shows "ALL" for a zone id of 0 despite it being an
invalid zone id. This could be manipulated server side to match newer
clients but there isn't much benefit since any other invalid zone id
below 0 can be used to do the same.

common/tasks.h

@@ -83,7 +83,8 @@ struct ActivityInformation {
 		if (zone_ids.empty()) {
 			return true;
 		}
-		bool found_zone = std::find(zone_ids.begin(), zone_ids.end(), zone_id) != zone_ids.end();
+		bool found_zone = std::any_of(zone_ids.begin(), zone_ids.end(),
+			[zone_id](int id) { return id <= 0 || id == zone_id; });
 
 		return found_zone && (zone_version == version || zone_version == -1);
 	}
@@ -100,7 +101,7 @@ struct ActivityInformation {
 			out.WriteInt32(activity_type == TaskActivityType::GiveCash ? 1 : goal_count);
 			out.WriteLengthString(skill_list); // used in SkillOn objective type string, "-1" for none
 			out.WriteLengthString(spell_list); // used in CastOn objective type string, "0" for none
-			out.WriteString(zones);            // used in objective zone column and task select "begins in" (may have multiple, "0" for "unknown zone", empty for "ALL")
+			out.WriteString(zones);            // used in ui zone columns and task select "begins in" (may have multiple, invalid id for "Unknown Zone", empty for "ALL")
 		}
 		else
 		{
@@ -114,7 +115,7 @@ struct ActivityInformation {
 		out.WriteString(description_override);
 
 		if (client_version >= EQ::versions::ClientVersion::RoF) {
-			out.WriteString(zones); // serialized again after description (seems unused)
+			out.WriteString(zones); // target zone version internal id (unused client side)
 		}
 	}