Remove transformers upper bound cap from install.py

The cap was wrong — it would downgrade transformers in shared venvs and
break other nodes. The torchcodec issue is handled in code now.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

install.py

@@ -20,7 +20,7 @@ pip("omnivoice", "--no-deps")
 # Install omnivoice's runtime inference dependencies (excludes torch, torchaudio,
 # gradio, tensorboardX, webdataset which are training/demo-only tools).
 pip(
-    "transformers>=4.40.0,<5.0.0",
+    "transformers>=4.40.0",
     "accelerate",
     "pydub",
     "soundfile",