Set can_generate for SpeechT5ForTextToSpeech (#25493)

add can_generate=True to SpeechT5ForTextToSpeech

src/transformers/models/speecht5/modeling_speecht5.py

@@ -2783,6 +2783,13 @@ class SpeechT5ForTextToSpeech(SpeechT5PreTrainedModel):
             encoder_attentions=outputs.encoder_attentions,
         )
 
+    def can_generate(self) -> bool:
+        """
+        Returns True. This model can `generate` and must therefore have this property set to True in order to be used
+        in the TTS pipeline.
+        """
+        return True
+
     @torch.no_grad()
     def generate(
         self,