Upgrade fern python generator (#758)

* make ServerMessage a discriminated union

* undo spec change, upgrade fern-python

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Co-authored-by: Thomas Baker <[email protected]>

Author: fern-support

fern/apis/api/generators.yml

@@ -11,7 +11,7 @@ groups:
   python-sdk:
     generators:
       - name: fernapi/fern-python-sdk
-        version: 4.31.1
+        version: 4.31.2
         api:
           settings:
             unions: v1