[bug-66216] fix issue where pivotTable.getPivotCacheDefinition() returns null

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1903445 13f79535-47bb-0310-9956-ffa450edef68

poi-ooxml/src/main/java/org/apache/poi/xssf/usermodel/XSSFPivotTable.java

@@ -97,6 +97,7 @@ public class XSSFPivotTable extends POIXMLDocumentPart {
         for (POIXMLDocumentPart documentPart : getRelations()) {
             if (documentPart instanceof XSSFPivotCacheDefinition) {
                 pivotCacheDefinition = (XSSFPivotCacheDefinition) documentPart;
+                break;
             }
         }
     }