[Quest API] Further char array cleanup. (#1634)

- Cleans up the rest of the char arrays used when exporting to events.
- Converts all events to use a similar variable name for export `export_string`.
- Needless calls to .c_str() removed.

zone/zoning.cpp

@@ -202,10 +202,8 @@ void Client::Handle_OP_ZoneChange(const EQApplicationPacket *app) {
 		return;
 	}
 
-	char buf[10];
-	snprintf(buf, 9, "%d", target_zone_id);
-	buf[9] = '\0';
-	parse->EventPlayer(EVENT_ZONE, this, buf, 0);
+	std::string export_string = fmt::format("{}", target_zone_id);
+	parse->EventPlayer(EVENT_ZONE, this, export_string, 0);
 
 	//handle circumvention of zone restrictions
 	//we need the value when creating the outgoing packet as well.