pytorch imple.: fix batch 1 inference from last commit

src/f5_tts/model/backbones/dit.py

@@ -238,6 +238,9 @@ class DiT(nn.Module):
         audio_mask: bool["b n"] | None = None,  # noqa: F722
     ):
         if self.text_uncond is None or self.text_cond is None or not cache:
+            if audio_mask is None:
+                text_embed = self.text_embed(text, x.shape[1], drop_text=drop_text, audio_mask=audio_mask)
+            else:
                 batch = x.shape[0]
                 seq_lens = audio_mask.sum(dim=1)
                 text_embed_list = []