[ArrowStringArray] PERF: small perf gain for object fallback (pandas-dev#41338)

Author: simonjayhawkins

pandas/core/arrays/string_arrow.py

@@ -792,7 +792,8 @@ def _str_map(self, f, na_value=None, dtype: Dtype | None = None):
             result = lib.map_infer_mask(
                 arr, f, mask.view("uint8"), convert=False, na_value=na_value
             )
-            return self._from_sequence(result)
+            result = pa.array(result, mask=mask, type=pa.string(), from_pandas=True)
+            return type(self)(result)
         else:
             # This is when the result type is object. We reach this when
             # -> We know the result type is truly object (e.g. .encode returns bytes