Fix mypy assignments errors

fastapi/_compat/main.py

@@ -35,7 +35,7 @@ if PYDANTIC_V2:
 else:
     from .v1 import BaseConfig as BaseConfig  # type: ignore[assignment]
     from .v1 import FieldInfo as FieldInfo
-    from .v1 import GenerateJsonSchema as GenerateJsonSchema
+    from .v1 import GenerateJsonSchema as GenerateJsonSchema  # type: ignore[assignment]
     from .v1 import (  # type: ignore[assignment]
         PydanticSchemaGenerationError as PydanticSchemaGenerationError,
     )

fastapi/openapi/utils.py

@@ -42,7 +42,9 @@ from .._compat import _is_model_field
 if PYDANTIC_V2:
     from .._compat.v2 import GenerateJsonSchema as GenerateJsonSchema
 else:
-    from .._compat.v1 import GenerateJsonSchema as GenerateJsonSchema
+    from .._compat.v1 import (  # type: ignore[assignment]
+        GenerateJsonSchema as GenerateJsonSchema,
+    )
 
 validation_error_definition = {
     "title": "ValidationError",