fix: remove packageManager field from package.json

The packageManager field was automatically added by yarn during
initial development but should not be present since jupyterlab-deepnote
uses jlpm (JupyterLab's yarn wrapper) for package management.

Author: devin-ai-integration[bot]

package.json

@@ -210,6 +210,5 @@
             "selector-no-vendor-prefix": null,
             "value-no-vendor-prefix": null
         }
-    },
-    "packageManager": "yarn@1.22.22+sha512.a6b2f7906b721bba3d67d4aff083df04dad64c399707841b7acf00f6b133b7ac24255f2652fa22ae3534329dc6180534e98d17432037ff6fd140556e2bb3137e"
+    }
 }