Ignore zero-length page_config.json, restore previous behavior of cra…

…shing for invalid JSON (#1405)

jupyter_server/config_manager.py

@@ -101,7 +101,7 @@ def get(self, section_name: str, include_root: bool = True) -> dict[str, t.Any]:
         )
         data: dict[str, t.Any] = {}
         for path in paths:
-            if os.path.isfile(path):
+            if os.path.isfile(path) and os.path.getsize(path):
                 with open(path, encoding="utf-8") as f:
                     try:
                         recursive_update(data, json.load(f))