BUG: Fix Series.str.contains with compiled regex on Arrow string dtype (#61942) and add whatsnew note

Author: Aniketsy

pandas/core/arrays/string_arrow.py

@@ -346,7 +346,7 @@ def _str_contains(
     ):
         if flags:
             return super()._str_contains(pat, case, flags, na, regex)
-        if isinstance(pat, re.pattern):
+        if isinstance(pat, re.Pattern):
             pat = pat.pattern
 
         return ArrowStringArrayMixin._str_contains(self, pat, case, flags, na, regex)