Construct the correct field name and strip out classes when searching

The classes were stripped out during when creating the field name but
it led to a wrong name.
Since class components in a path are irrelevant, they're just ignored
when searching for a node in the datasets.

src/core/xml_parser.js

@@ -354,6 +354,11 @@ class SimpleDOMNode {
     }
 
     const component = paths[pos];
+    if (component.name.startsWith("#") && pos < paths.length - 1) {
+      // If it starts with a # then it's a class which is not a concept for
+      // datasets elements (https://www.pdfa.org/norm-refs/XFA-3_3.pdf#page=96).
+      return this.searchNode(paths, pos + 1);
+    }
     const stack = [];
     let node = this;