[fix] engine mullvadleta - ignore HTTP 403 & 429 response

It doesn't matter if you're using Mullvad's VPN and a proper browser, you'll
still get blocked for specific searches [1] with a 403 or 429 HTTP status code.
Mullvad only blocks the search request and doesn't prevent you from doing more
searches.

The logic should handle the blocked requests (403, 429), but not put the engine
on a cooldown.

[1] https://leta.mullvad.net/search?q=site%3Afoo+bar&engine=brave

Closes: https://github.com/searxng/searxng/issues/5328
Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>

searx/engines/mullvad_leta.py

@@ -43,9 +43,12 @@ import babel
 from httpx import Response
 from lxml import html
 from searx.enginelib.traits import EngineTraits
+from searx.extended_types import SXNG_Response
+
 from searx.locales import get_official_locales, language_tag, region_tag
 from searx.utils import eval_xpath_list
 from searx.result_types import EngineResults, MainResult
+from searx.network import raise_for_httperror
 
 search_url = "https://leta.mullvad.net"
 
@@ -112,7 +115,8 @@ class DataNodeResultIndices(t.TypedDict):
     favicon: int
 
 
-def request(query: str, params: dict):
+def request(query: str, params: dict[str, t.Any]) -> None:
+    params["raise_for_httperror"] = False
     params["method"] = "GET"
     args = {
         "q": query,
@@ -136,10 +140,19 @@ def request(query: str, params: dict):
 
     params["url"] = f"{search_url}/search/__data.json?{urlencode(args)}"
 
-    return params
 
+def response(resp: SXNG_Response) -> EngineResults:
+    results = EngineResults()
+
+    if resp.status_code in (403, 429):
+        # It doesn't matter if you're using Mullvad's VPN and a proper browser,
+        # you'll still get blocked for specific searches with a 403 or 429 HTTP
+        # status code.
+        # https://github.com/searxng/searxng/issues/5328#issue-3518337233
+        return results
+    # raise for other errors
+    raise_for_httperror(resp)
 
-def response(resp: Response) -> EngineResults:
     json_response = resp.json()
 
     nodes = json_response["nodes"]
@@ -159,7 +172,6 @@ def response(resp: Response) -> EngineResults:
 
     query_items_indices = query_meta_data["items"]
 
-    results = EngineResults()
     for idx in data_nodes[query_items_indices]:
         query_item_indices: DataNodeResultIndices = data_nodes[idx]
         results.add(