fix: ollama chat completion needs unique ids

The chat completion ids generated by Ollama are not unique enough to
use with stored chat completions as they rely on only 3 numbers of
randomness to give unique values - ie `chatcmpl-373`. This causes
frequent collisions in id values of chat completions in Ollama, which
creates issues in our SQL storage of chat completions by id where it
expects ids to actually be unique.

So, this adjusts Ollama responses to use uuids as unique ids. This
does mean we're replacing the ids generated natively by Ollama. If we
don't wish to do this, we'll either need to relax the unique
constraint on our chat completions id field in the inference storage
or convince Ollama upstream to use something closer to uuid values
here.

Closes #2315

I tested by running the openai completion / chat completion
integration tests in a loop. Without this change, I regularly get
unique id collisions. With this change, I do not.

```
INFERENCE_MODEL="meta-llama/Llama-3.2-3B-Instruct" \
llama stack run llama_stack/templates/ollama/run.yaml

while true; do; \
  INFERENCE_MODEL="meta-llama/Llama-3.2-3B-Instruct" \
  pytest -s -v \
    tests/integration/inference/test_openai_completion.py \
    --stack-config=http://localhost:8321 \
    --text-model="meta-llama/Llama-3.2-3B-Instruct"; \
done
```

Signed-off-by: Ben Browning <bbrownin@redhat.com>

llama_stack/providers/remote/inference/ollama/ollama.py

@@ -5,6 +5,7 @@
 # the root directory of this source tree.
 
 
+import uuid
 from collections.abc import AsyncGenerator, AsyncIterator
 from typing import Any
 
@@ -480,7 +481,25 @@ class OllamaInferenceAdapter(
             top_p=top_p,
             user=user,
         )
-        return await self.openai_client.chat.completions.create(**params)  # type: ignore
+        response = await self.openai_client.chat.completions.create(**params)
+        return await self._adjust_ollama_chat_completion_response_ids(response)
+
+    async def _adjust_ollama_chat_completion_response_ids(
+        self,
+        response: OpenAIChatCompletion | AsyncIterator[OpenAIChatCompletionChunk],
+    ) -> OpenAIChatCompletion | AsyncIterator[OpenAIChatCompletionChunk]:
+        id = f"chatcmpl-{uuid.uuid4()}"
+        if isinstance(response, AsyncIterator):
+
+            async def stream_with_chunk_ids() -> AsyncIterator[OpenAIChatCompletionChunk]:
+                async for chunk in response:
+                    chunk.id = id
+                    yield chunk
+
+            return stream_with_chunk_ids()
+        else:
+            response.id = id
+            return response
 
     async def batch_completion(
         self,