Fix AttributeError from _supports_sdpa read before language_model exists

Florence2PreTrainedModel._supports_sdpa/_supports_flash_attn_2 are properties that forward to self.language_model._supports_sdpa. But self.language_model is only assigned partway through Florence2ForConditionalGeneration.__init__, after super().__init__(config) runs -- and this transformers version's PreTrainedModel.__init__ now reads self._supports_sdpa during that super().__init__() call, before language_model exists.

The resulting AttributeError from the inner self.language_model access gets silently reinterpreted by Python's descriptor protocol (property getter raises AttributeError -> falls through to nn.Module.__getattr__ -> raises a new AttributeError naming the outer attribute) -- hence the confusing "no attribute '_supports_sdpa'" message instead of the real cause.

Fall back to True (the constant Florence2LanguageForConditionalGeneration always declares for both flags) when language_model isn't set yet.

modeling_florence2.py

@@ -2335,17 +2335,26 @@ class Florence2PreTrainedModel(PreTrainedModel):
     def _supports_flash_attn_2(self):
         """
         Retrieve language_model's attribute to check whether the model supports
-        Flash Attention 2 or not.
+        Flash Attention 2 or not. PreTrainedModel.__init__ reads this before
+        self.language_model is assigned (it's set partway through this class's
+        own __init__, after super().__init__() runs), so fall back to the
+        constant Florence2LanguageForConditionalGeneration always declares.
         """
-        return self.language_model._supports_flash_attn_2
+        language_model = getattr(self, "language_model", None)
+        if language_model is None:
+            return True
+        return language_model._supports_flash_attn_2
 
     @property
     def _supports_sdpa(self):
         """
         Retrieve language_model's attribute to check whether the model supports
-        SDPA or not.
+        SDPA or not. Same early-access issue as _supports_flash_attn_2 above.
         """
-        return self.language_model._supports_sdpa
+        language_model = getattr(self, "language_model", None)
+        if language_model is None:
+            return True
+        return language_model._supports_sdpa
 
 
 FLORENCE2_INPUTS_DOCSTRING = r"""