[refactor] engines: use datetime.fromisoformat instead of datetime.strptime where possible (#6394)

Refactor engines that parse ISO 8601 dates with strptime to use
fromisoformat instead. In most cases this is a direct replacement of
strptime(text, "format") with fromisoformat(text).

For engines where the source has a trailing "Z" that strptime consumed
as a literal (e.g. "%Y-%m-%dT%H:%M:%S.%fZ" in huggingface.py), add
rstrip("Z") to keep the output naive and preserve the existing behavior.

In sogou.py the date is extracted with a regular expression, which can
yield strings like "2026-7-11". strptime accepts this via its format
string, but fromisoformat does not. To preserve the existing behavior
and satisfy the format fromisoformat expects, add zero-padding for the
month and day.

Closes: #6098
---------
Signed-off-by: OneVth <onebrotravel@gmail.com>

searx/engines/sogou.py

@@ -95,7 +95,8 @@ def _parse_date(text):
         date_match = re.search(r"(\d{4}-\d{1,2}-\d{1,2})", text)
         if date_match:
             try:
-                return datetime.strptime(date_match.group(1), "%Y-%m-%d")
+                y, m, d = date_match.group(1).split("-")
+                return datetime(year=int(y), month=int(m), day=int(d))
             except (ValueError, TypeError):
                 pass
     return None