feat: support filters in file search (#2472)

# What does this PR do?
Move to use vector_stores.search for file search tool in Responses,
which supports filters.

closes #2435 

## Test Plan
Added e2e test with fitlers.
myenv ❯ llama stack run llama_stack/templates/fireworks/run.yaml

pytest -sv tests/verifications/openai_api/test_responses.py \
  -k 'file_search and filters' \
  --base-url=http://localhost:8321/v1/openai/v1 \
  --model=meta-llama/Llama-3.3-70B-Instruct

llama_stack/providers/inline/agents/meta_reference/agents.py

@@ -85,6 +85,7 @@ class MetaReferenceAgentsImpl(Agents):
             tool_groups_api=self.tool_groups_api,
             tool_runtime_api=self.tool_runtime_api,
             responses_store=self.responses_store,
+            vector_io_api=self.vector_io_api,
         )
 
     async def create_agent(