refactor(taps): Use CursorResult.mappings() in SQL streams (#2095)

* refactor(taps): Use `CursorResult.mappings()` in SQL streams

* Avoid segmentation fault in SQLAlchemy 1.4???

* Remove redundant `.all()`

singer_sdk/streams/sql.py

@@ -213,8 +213,10 @@ def get_records(self, context: dict | None) -> t.Iterable[dict[str, t.Any]]:
             query = query.limit(self.ABORT_AT_RECORD_COUNT + 1)
 
         with self.connector._connect() as conn:
-            for record in conn.execute(query):
-                transformed_record = self.post_process(dict(record._mapping))
+            for record in conn.execute(query).mappings():
+                # TODO: Standardize record mapping type
+                # https://github.com/meltano/sdk/issues/2096
+                transformed_record = self.post_process(dict(record))
                 if transformed_record is None:
                     # Record filtered out during post_process()
                     continue