Added check null for extracted json value for column value (#500)

Co-authored-by: Rakhi Agrawal <rakagrawal@linkedin.com>

Author: rakhiagr

dao-impl/ebean-dao/src/main/java/com/linkedin/metadata/dao/EbeanLocalRelationshipQueryDAO.java

@@ -374,9 +374,12 @@ private <SNAPSHOT extends RecordTemplate> SNAPSHOT constructSnapshot(@Nonnull fi
       String auditedAspectStr = sqlRow.getString(colName);
 
       if (auditedAspectStr != null) {
-        RecordTemplate aspect = RecordUtils.toRecordTemplate(ClassUtils.loadClass(aspectCanonicalName),
-            EBeanDAOUtils.extractAspectJsonString(auditedAspectStr));
-        aspects.add(ModelUtils.newAspectUnion(ModelUtils.getUnionClassFromSnapshot(snapshotClass), aspect));
+        String extractedAspectStr = EBeanDAOUtils.extractAspectJsonString(auditedAspectStr);
+        if (extractedAspectStr != null) {
+          RecordTemplate aspect = RecordUtils.toRecordTemplate(ClassUtils.loadClass(aspectCanonicalName),
+              extractedAspectStr);
+          aspects.add(ModelUtils.newAspectUnion(ModelUtils.getUnionClassFromSnapshot(snapshotClass), aspect));
+        }
       }
     }