[Port dspace-8_x] fix(#10721): Sanitize non-characters during OAI indexing (#11397)

* fix(#10721): Sanitize non-characters during OAI indexing

(cherry picked from commit ad890b0661)

* refactor: Use StringEscapeUtils as suggested in review

(cherry picked from commit 0ddd5ad575)

* fix: Removed whitespace before the import that was causing error

Maven Unit Test failed due to the whitespace before the import
https://github.com/DSpace/DSpace/actions/runs/16891881837/job/47853392956?pr=11139#step:4:1959

(cherry picked from commit 406bffdcca)

* fix: Removed trailing whitespace that was causing error

(cherry picked from commit 266ac423b4)

---------

Co-authored-by: JohnnyMendesC <177888064+JohnnyMendesC@users.noreply.github.com>

dspace-oai/src/main/java/org/dspace/xoai/util/ItemUtils.java

@@ -18,6 +18,7 @@ import java.util.List;
 import com.lyncode.xoai.dataprovider.xml.xoai.Element;
 import com.lyncode.xoai.dataprovider.xml.xoai.Metadata;
 import com.lyncode.xoai.util.Base64Utils;
+import org.apache.commons.text.StringEscapeUtils;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.dspace.app.util.factory.UtilServiceFactory;
@@ -165,6 +166,19 @@ public class ItemUtils {
         return bundles;
     }
 
+    /**
+     * Sanitizes a string to remove characters that are invalid
+     * in XML 1.0 using the Apache Commons Text library.
+     * @param value The string to sanitize.
+     * @return A sanitized string, or null if the input was null.
+     */
+    private static String sanitize(String value) {
+        if (value == null) {
+            return null;
+        }
+        return StringEscapeUtils.escapeXml10(value);
+    }
+
     /**
      * This method will add metadata information about associated resource policies for a give bitstream.
      * It will parse of relevant policies and add metadata information
@@ -281,7 +295,7 @@ public class ItemUtils {
             valueElem = language;
         }
 
-        valueElem.getField().add(createValue("value", val.getValue()));
+        valueElem.getField().add(createValue("value", sanitize(val.getValue())));
         if (val.getAuthority() != null) {
             valueElem.getField().add(createValue("authority", val.getAuthority()));
             if (val.getConfidence() != Choices.CF_NOVALUE) {