pw_presubmit: Remove unnecessary default values

Bug: b/233808334
Change-Id: I0247355289f725e7940cb40722d8d4c4faac9f78
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/110330
Commit-Queue: Auto-Submit <auto-submit@pigweed.google.com.iam.gserviceaccount.com>
Reviewed-by: Wyatt Hepler <hepler@google.com>
Pigweed-Auto-Submit: Rob Mohr <mohrr@google.com>
diff --git a/pw_presubmit/py/pw_presubmit/presubmit.py b/pw_presubmit/py/pw_presubmit/presubmit.py
index 7c26822..75b3433 100644
--- a/pw_presubmit/py/pw_presubmit/presubmit.py
+++ b/pw_presubmit/py/pw_presubmit/presubmit.py
@@ -211,10 +211,8 @@
     output_dir: Path
     paths: Tuple[Path, ...]
     package_root: Path
-    luci: Optional[LuciContext] = None
-    # TODO(b/233808334): Remove default value after updating downstream
-    # projects to use this new value.
-    override_gn_args: Dict[str, str] = dataclasses.field(default_factory=dict)
+    luci: Optional[LuciContext]
+    override_gn_args: Dict[str, str]
     _failed: bool = False
 
     @property