6.03.00044 Bale Collector: skip invalid bales (#6859)

Some bales seem to have a node ID of 0, attempt to skip them
when scanning the field.

modDesc.xml

@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="utf-8" standalone="no" ?>
 <modDesc descVersion="47">
-	<version>6.03.00043</version>
+	<version>6.03.00044</version>
 	<author><![CDATA[Courseplay.devTeam]]></author>
 	<title><!-- en=English de=German fr=French es=Spanish ru=Russian pl=Polish it=Italian br=Brazilian-Portuguese cs=Chinese(Simplified) ct=Chinese(Traditional) cz=Czech nl=Netherlands hu=Hungary jp=Japanese kr=Korean pt=Portuguese ro=Romanian tr=Turkish -->
 		<en>CoursePlay SIX</en>