chart: change index importer nodeAffinity to preferred not required

Author: ikreymer

chart/app-templates/index-import-job.yaml

@@ -69,7 +69,7 @@ spec:
       affinity:
     {% if crawler_node_type %}
         nodeAffinity:
-          requiredDuringSchedulingIgnoredDuringExecution:
+          preferredDuringSchedulingIgnoredDuringExecution:
             nodeSelectorTerms:
               - matchExpressions:
                 - key: nodeType