[optim] add support to APOLLO (#6617)

Former-commit-id: 5a252e5a458457adbd19da3b68a3897ad2962824

src/llamafactory/extras/packages.py

@@ -49,6 +49,8 @@ def is_fastapi_available():
 def is_galore_available():
     return _is_package_available("galore_torch")
 
+def is_apollo_available():
+    return _is_package_available("apollo_torch")
 
 def is_gradio_available():
     return _is_package_available("gradio")