Update xmp metadata if it was present in document before close

This includes cases if user manually set xmp metadata, or if it was
present in modified document.

DEVSIX-1870

Author: IdamkinI

kernel/src/main/java/com/itextpdf/kernel/pdf/PdfDocument.java

@@ -1805,7 +1805,7 @@ protected void addCustomMetadataExtensions(XMPMeta xmpMeta) {
      */
     protected void updateXmpMetadata() {
         try {
-            if (writer.properties.addXmpMetadata) {
+            if (xmpMetadata != null || writer.properties.addXmpMetadata) {
                 setXmpMetadata(updateDefaultXmpMetadata());
             }
         } catch (XMPException e) {

kernel/src/test/java/com/itextpdf/kernel/pdf/XMPMetadataTest.java

@@ -42,6 +42,7 @@ This file is part of the iText (R) project.
  */
 package com.itextpdf.kernel.pdf;
 
+import com.itextpdf.io.LogMessageConstant;
 import com.itextpdf.kernel.utils.CompareTool;
 import com.itextpdf.kernel.xmp.PdfConst;
 import com.itextpdf.kernel.xmp.XMPConst;
@@ -51,6 +52,8 @@ This file is part of the iText (R) project.
 import com.itextpdf.kernel.xmp.XMPUtils;
 import com.itextpdf.kernel.xmp.options.SerializeOptions;
 import com.itextpdf.test.ExtendedITextTest;
+import com.itextpdf.test.annotations.LogMessage;
+import com.itextpdf.test.annotations.LogMessages;
 import com.itextpdf.test.annotations.type.IntegrationTest;
 
 import java.io.ByteArrayInputStream;
@@ -179,6 +182,9 @@ public void emptyDocumentWithXmpAppendMode02() throws Exception {
 
 
     @Test
+    @LogMessages(messages = {
+            @LogMessage(messageTemplate = LogMessageConstant.EXCEPTION_WHILE_UPDATING_XMPMETADATA)
+    })
     public void createEmptyDocumentWithAbcXmp() throws IOException, XMPException {
         ByteArrayOutputStream fos = new ByteArrayOutputStream();
         PdfWriter writer = new PdfWriter(fos);