prompty: expose the 'model' property for use in flex flows

Useful in flex flows  for instance to adapt the external logic to some conditions
(.i.e if the api is chat or completion, if it is streaming or not, etc).

src/promptflow-core/promptflow/core/__init__.py

@@ -12,6 +12,7 @@
     AzureOpenAIModelConfiguration,
     ModelConfiguration,
     OpenAIModelConfiguration,
+    PromptyModelConfiguration
 )
 
 from ._version import __version__
@@ -29,6 +30,7 @@
     "AsyncPrompty",
     "ModelConfiguration",
     "OpenAIModelConfiguration",
+    "PromptyModelConfiguration",
     "AzureOpenAIModelConfiguration",
     "__version__",
 ]

src/promptflow-core/promptflow/core/_flow.py

@@ -377,6 +377,13 @@ def _parse_prompty(path):
         config_content, prompt_template = result.groups()
         configs = load_yaml_string(config_content)
         return configs, prompt_template
+
+    @property
+    def model(self) -> PromptyModelConfiguration:
+        """
+        Returns the parsed and resolved model configuration associated with this object.
+        """
+        return self._model
 
     def _resolve_inputs(self, input_values):
         """