Switch transform to new dict-template format (drops jmespath)

tokenizer_config.json

@@ -96,7 +96,13 @@
             ]
           ]
         },
-        "transform": "{type: 'function', function: {name: name, arguments: content}}"
+        "transform": {
+          "type": "function",
+          "function": {
+            "name": "{name}",
+            "arguments": "{content}"
+          }
+        }
       },
       "content": {
         "close": [