community: minor changes sambanova integration (#21231)

- **Description:** fix: variable names in root validator not allowing
pass credentials as named parameters in llm instancing, also added
sambanova's sambaverse and sambastudio llms to __init__.py for module
import

libs/community/tests/unit_tests/llms/test_imports.py

@@ -77,6 +77,8 @@ EXPECT_ALL = [
     "RWKV",
     "Replicate",
     "SagemakerEndpoint",
+    "Sambaverse",
+    "SambaStudio",
     "SelfHostedHuggingFaceLLM",
     "SelfHostedPipeline",
     "StochasticAI",