[unbload] drop meaningless field `number_of_results_xpath` from results (#6130)

In the result-list, the ``number_of_results`` indicate the number of hits in the
Index, they do not indicate how many results are in the answer.

In the past, search engines such as google or ddg had an indication on the first
page of a search term of how many hits there were for this term in total in
their index.

This info was added up in SearXNG and delivered under ``number_of_results``.
Nowadays the search engines no longer indicate how many hits there are in the
index and so this field in SearXNG is also superfluous.

- https://github.com/searxng/searxng/issues/2457#issuecomment-2566181574
- https://github.com/searxng/searxng/issues/2987
- https://github.com/searxng/searxng/issues/5034

Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>

searx/engines/duden.py

@@ -1,7 +1,6 @@
 # SPDX-License-Identifier: AGPL-3.0-or-later
 """Duden"""
 
-import re
 from urllib.parse import quote, urljoin
 from lxml import html
 from searx.utils import extract_text, eval_xpath, eval_xpath_list, eval_xpath_getindex
@@ -51,13 +50,6 @@ def response(resp):
 
     dom = html.fromstring(resp.text)
 
-    number_of_results_element = eval_xpath_getindex(
-        dom, '//a[@class="active" and contains(@href,"/suchen/dudenonline")]/span/text()', 0, default=None
-    )
-    if number_of_results_element is not None:
-        number_of_results_string = re.sub('[^0-9]', '', number_of_results_element)
-        results.append({'number_of_results': int(number_of_results_string)})
-
     for result in eval_xpath_list(dom, '//section[not(contains(@class, "essay"))]'):
         url = eval_xpath_getindex(result, './/h2/a', 0).get('href')
         url = urljoin(base_url, url)