[Attention] Small fix on output attentions (#38948)

small fix

Author: vasqu

src/transformers/configuration_utils.py

@@ -338,7 +338,7 @@ def output_attentions(self):
 
     @output_attentions.setter
     def output_attentions(self, value):
-        if self._attn_implementation != "eager":
+        if value is True and self._attn_implementation != "eager":
             raise ValueError(
                 "The `output_attentions` attribute is not supported when using the `attn_implementation` set to "
                 f"{self._attn_implementation}. Please set it to 'eager' instead."