NIFI-8933 Configure Jersey's ObjectMapper to ingnore unknown fields

Signed-off-by: Pierre Villard <pierre.villard.fr@gmail.com>

This closes #5236.
diff --git a/nifi-commons/nifi-web-utils/src/main/java/org/apache/nifi/web/util/ObjectMapperResolver.java b/nifi-commons/nifi-web-utils/src/main/java/org/apache/nifi/web/util/ObjectMapperResolver.java
index d1b4036..9333913 100644
--- a/nifi-commons/nifi-web-utils/src/main/java/org/apache/nifi/web/util/ObjectMapperResolver.java
+++ b/nifi-commons/nifi-web-utils/src/main/java/org/apache/nifi/web/util/ObjectMapperResolver.java
@@ -18,6 +18,7 @@
 
 import com.fasterxml.jackson.annotation.JsonInclude.Include;
 import com.fasterxml.jackson.annotation.JsonInclude.Value;
+import com.fasterxml.jackson.databind.DeserializationFeature;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.fasterxml.jackson.module.jaxb.JaxbAnnotationIntrospector;
 
@@ -29,10 +30,11 @@
 
     private final ObjectMapper mapper;
 
-    public ObjectMapperResolver() throws Exception {
+    public ObjectMapperResolver() {
         mapper = new ObjectMapper();
         mapper.setDefaultPropertyInclusion(Value.construct(Include.NON_NULL, Include.ALWAYS));
         mapper.setAnnotationIntrospector(new JaxbAnnotationIntrospector(mapper.getTypeFactory()));
+        mapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
     }
 
     @Override
diff --git a/nifi-registry/nifi-registry-core/nifi-registry-data-model/src/main/java/org/apache/nifi/registry/flow/VersionedProcessGroup.java b/nifi-registry/nifi-registry-core/nifi-registry-data-model/src/main/java/org/apache/nifi/registry/flow/VersionedProcessGroup.java
index c3df8ca..06ce83f 100644
--- a/nifi-registry/nifi-registry-core/nifi-registry-data-model/src/main/java/org/apache/nifi/registry/flow/VersionedProcessGroup.java
+++ b/nifi-registry/nifi-registry-core/nifi-registry-data-model/src/main/java/org/apache/nifi/registry/flow/VersionedProcessGroup.java
@@ -200,7 +200,7 @@
 
     @ApiModelProperty(value = "Default value used in this Process Group for the maximum data size of objects that can be queued before back pressure is applied.")
     public String getDefaultBackPressureDataSizeThreshold() {
-        return defaultBackPressureDataSizeThreshold == null ? "" : defaultBackPressureDataSizeThreshold;
+        return defaultBackPressureDataSizeThreshold;
     }
 
     public void setDefaultBackPressureDataSizeThreshold(final String defaultBackPressureDataSizeThreshold) {