Fix incorrect completion() signature for Databricks provider

Signed-off-by: Yuan Tang <[email protected]>

llama_stack/providers/adapters/inference/databricks/databricks.py

@@ -48,7 +48,14 @@ async def initialize(self) -> None:
     async def shutdown(self) -> None:
         pass
 
-    def completion(self, request: CompletionRequest) -> AsyncGenerator:
+    def completion(
+        self,
+        model: str,
+        content: InterleavedTextMedia,
+        sampling_params: Optional[SamplingParams] = SamplingParams(),
+        stream: Optional[bool] = False,
+        logprobs: Optional[LogProbConfig] = None,
+    ) -> AsyncGenerator:
         raise NotImplementedError()
 
     def chat_completion(