Default parse-time nodes' raw_code property to "" (empty string) to comply with strict str type (#11884)

* Default parse-time nodes' raw_code property to "" (empty string) to comply with strict str type

* Changelog entry

---------

Co-authored-by: Doug Beatty <[email protected]>

Author: wircho

.changes/unreleased/Fixes-20250804-074254.yaml

@@ -0,0 +1,6 @@
+kind: Fixes
+body: Comply with strict `str` type when `block.contents` is `None`
+time: 2025-08-04T07:42:54.612616-06:00
+custom:
+    Author: wircho
+    Issue: "11492"

core/dbt/parser/base.py

@@ -244,7 +244,7 @@ def _create_parsetime_node(
             "path": path,
             "original_file_path": block.path.original_file_path,
             "package_name": self.project.project_name,
-            "raw_code": block.contents,
+            "raw_code": block.contents or "",
             "language": language,
             "unique_id": self.generate_unique_id(name),
             "config": self.config_dict(config),