[Fix kbss-cvut/record-manager-ui#185] Fix exported excel is empty in …

…operator

- make fha question and section optional

src/main/resources/query/find-raw-records.sparql

@@ -24,11 +24,14 @@ SELECT ?r (?r as ?uri)
     GRAPH ?r {
         ?r rm:has-question ?f.
         ?f doc:has_related_question ?s1.
-        ?f doc:has_related_question ?s2.
-        FILTER(?s2 != ?s1)
-        ?s2 doc:has_related_question ?fhaEventQ.
-        ?fhaEventQ form:has-question-origin ?fhaEventQuestionOrigin.
-        FILTER(contains(str(?fhaEventQuestionOrigin), "http://vfn.cz/ontologies/ava-study/model/fha-event"))
+
+        OPTIONAL{
+            ?f doc:has_related_question ?s2.
+            FILTER(?s2 != ?s1)
+            ?s2 doc:has_related_question ?fhaEventQ.
+            ?fhaEventQ form:has-question-origin ?fhaEventQuestionOrigin.
+            FILTER(contains(str(?fhaEventQuestionOrigin), "http://vfn.cz/ontologies/ava-study/model/fha-event"))
+        }
 
         ?s1 doc:has_related_question ?FUSq.
         ?FUSq form:has-question-origin avamod:fuselage-no.