fix: Safety in starter (#2731)

- fireworks, together do not support Llama-guard 3 8b model anymore 
- Need to default to ollama 
- current safety shields logic was not correct since the shield_id was
the provider ( which had duplicates )
- Followed similar logic to models 

Note: Seems a bit over-engineered but this can now be extended to other
providers and fits in the overall mechanism of how env_vars are used to
manage starter.

### How to test 
```
ENABLE_OLLAMA=ollama ENABLE_FIREWORKS=fireworks SAFETY_MODEL=llama-guard3:1b pytest -s -v tests/integration/ --stack-config starter -k 'not(supervised_fine_tune or builtin_tool_code or safety_with_image or code_interpreter_for or rag_and_code or truncation or register_and_unregister)' --text-model fireworks/meta-llama/Llama-3.3-70B-Instruct --vision-model fireworks/meta-llama/Llama-4-Scout-17B-16E-Instruct --safety-shield llama-guard3:1b --embedding-model all-MiniLM-L6-v2
```

### Related but not obvious in this PR 
In the llama-stack-ops repo, we run tests before publishing packages and
docker containers.
The actions in that repo were using the fireworks / together distros (
which are non-existent )

So need to update that to run with `starter` and use `ollama`
specifically for safety.

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

@@ -12,6 +12,19 @@ from llama_stack.providers.utils.inference.model_registry import (
     build_model_entry,
 )
 
+SAFETY_MODELS_ENTRIES = [
+    # The Llama Guard models don't have their full fp16 versions
+    # so we are going to alias their default version to the canonical SKU
+    build_hf_repo_model_entry(
+        "llama-guard3:8b",
+        CoreModelId.llama_guard_3_8b.value,
+    ),
+    build_hf_repo_model_entry(
+        "llama-guard3:1b",
+        CoreModelId.llama_guard_3_1b.value,
+    ),
+]
+
 MODEL_ENTRIES = [
     build_hf_repo_model_entry(
         "llama3.1:8b-instruct-fp16",
@@ -73,16 +86,6 @@ MODEL_ENTRIES = [
         "llama3.3:70b",
         CoreModelId.llama3_3_70b_instruct.value,
     ),
-    # The Llama Guard models don't have their full fp16 versions
-    # so we are going to alias their default version to the canonical SKU
-    build_hf_repo_model_entry(
-        "llama-guard3:8b",
-        CoreModelId.llama_guard_3_8b.value,
-    ),
-    build_hf_repo_model_entry(
-        "llama-guard3:1b",
-        CoreModelId.llama_guard_3_1b.value,
-    ),
     ProviderModelEntry(
         provider_model_id="all-minilm:l6-v2",
         aliases=["all-minilm"],
@@ -100,4 +103,4 @@ MODEL_ENTRIES = [
             "context_length": 8192,
         },
     ),
-]
+] + SAFETY_MODELS_ENTRIES