fix(py): Fix pyproject.toml on fastapi plugin (#5030)

Author: huangjeff5

py/plugins/fastapi/pyproject.toml

@@ -66,4 +66,4 @@ build-backend = "hatchling.build"
 requires      = ["hatchling"]
 
 [tool.hatch.build.targets.wheel]
-packages = ["src/genkit", "src/genkit/plugins"]
+packages = ["src/genkit"]