fix mypy errors from types-peewee 4.0 (#24323)

types-peewee 4.0 types model fields precisely, so 17 `type: ignore` comments and 2 `cast(str, ...)` calls are no longer needed. Its stubs type `.namedtuples()` and `.dicts()` queries as returning model instances, so the review cleanup reads namedtuple fields by name and the storage usage query casts its dict rows. `start_time` is declared `DateTimeField` but stores unix timestamps, so two reads cast it like `debug_replay.py` already does. `Export` gets an annotation for the `export_case_id` attribute peewee adds at runtime.

frigate/data_processing/post/object_descriptions.py

@@ -253,7 +253,7 @@ class ObjectDescriptionProcessor(PostProcessorApi):
             # Crop snapshot based on region
             # provide full image if region doesn't exist (manual events)
             height, width = img.shape[:2]
-            x1_rel, y1_rel, width_rel, height_rel = event.data.get(  # type: ignore[attr-defined]
+            x1_rel, y1_rel, width_rel, height_rel = event.data.get(
                 "region", [0, 0, 1, 1]
             )
             x1, y1 = int(x1_rel * width), int(y1_rel * height)