Fix model mapping for AnthropicChat and AnthropicCompletions (#3453)

Previous values for "anthropic-chat" and "anthropic-chat-completions" did not exist as classes. I swapped them out with the correct class, namely "lm_eval.models.anthropic_llms:AnthropicChat"

Author: lucafossen

lm_eval/models/__init__.py

@@ -23,8 +23,8 @@
 """
 
 MODEL_MAPPING = {
-    "anthropic-chat": "lm_eval.models.anthropic_llms:AnthropicChatLM",
-    "anthropic-chat-completions": "lm_eval.models.anthropic_llms:AnthropicCompletionsLM",
+    "anthropic-chat": "lm_eval.models.anthropic_llms:AnthropicChat",
+    "anthropic-chat-completions": "lm_eval.models.anthropic_llms:AnthropicChat",
     "anthropic-completions": "lm_eval.models.anthropic_llms:AnthropicLM",
     "dummy": "lm_eval.models.dummy:DummyLM",
     "ggml": "lm_eval.models.gguf:GGUFLM",