refactor: simplify embedding connection test by removing unused endpoint param

The endpoint parameter was never used for embedding models, only for LLMs. Remove it from _test_embedding_connection

Author: EmanueleDeRossi1

apps/backend/src/rhesis/backend/app/services/model_connection.py

@@ -179,23 +179,17 @@ def _test_language_model_connection(
 
     @staticmethod
     def _test_embedding_connection(
-        provider: str, model_name: str, api_key: str, endpoint: str | None = None
+        provider: str, model_name: str, api_key: str | None = None
     ) -> ModelConnectionTestResult:
         """Test an embedding model connection."""
         try:
             from rhesis.sdk.models.factory import EmbeddingModelConfig, get_embedding_model
 
-            # Build extra params for providers that need them
-            extra_params = {}
-            if endpoint:
-                extra_params["base_url"] = endpoint
-
             # Create embedder config
             config = EmbeddingModelConfig(
                 provider=provider,
                 model_name=model_name,
                 api_key=api_key,
-                extra_params=extra_params,
             )
 
             # Try to create the embedder instance