llama4 support (#2493)

* llama4 support

* add xet support [skip ci]

* be flexible on transformers version and skip test on version

* don't use deepspeed for the fix_untrained_tokens test

* reordering to trigger torch 2.6.0 tests first

* slightly smaller train set

* use 4.51.0 for now

* remove stray print, add llama4 chat template to schema, bump peft to 0.15.1

* patches to make llama4 performant

* add preliminary fp8 support

src/axolotl/monkeypatch/multipack.py

@@ -13,6 +13,7 @@ from axolotl.monkeypatch.utils import get_unpad_data
 SUPPORTED_MULTIPACK_MODEL_TYPES = [
     "mllama_text_model",
     "llama",
+    "llama4",
     "mistral",
     "mixtral",
     "qwen2",