Remove root element wrapper when parsing XML string

Author: chiranSachintha

bvm/ballerina-runtime/src/main/java/io/ballerina/runtime/internal/TypeConverter.java

@@ -973,7 +973,7 @@ public static BDecimal stringToDecimal(String value) throws NumberFormatExceptio
     }
 
     public static BXml stringToXml(String value) throws BError {
-        BXml item = XmlUtils.parse("<root>" + value + "</root>");
+        BXml item = XmlUtils.parse(value);
         return item.children();
     }