Feat/add llama 4 (#316)

* feat: add llama4 model

* fix: remove autogen & pump litellm gpt4.1 fallback fix

* fix: use commit that have no upstream update litellm

* fix: pump litellm version

* fix: pump litellm with gpt4.1 fix

Author: ducphamle2

openhands/llm/llm.py

@@ -79,6 +79,7 @@
     'grok-3-mini',
     'grok-3-mini-beta',
     'skylark-prod-250415',
+    'llama-4-maverick',
 ]
 
 REASONING_EFFORT_SUPPORTED_MODELS = [