fix: make telemetry optional for agents (#3705)

# What does this PR do?

there is a lot of code in the agents API using the telemetry API and its
helpers without checking if that API is even enabled.

This is the only API besides inference actively using telemetry code, so
after this telemetry can be optional for the entire stack


resolves #3665


## Test Plan

existing agent tests.

Signed-off-by: Charlie Doern <cdoern@redhat.com>

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

@@ -64,6 +64,7 @@ class MetaReferenceAgentsImpl(Agents):
         tool_runtime_api: ToolRuntime,
         tool_groups_api: ToolGroups,
         policy: list[AccessRule],
+        telemetry_enabled: bool = False,
     ):
         self.config = config
         self.inference_api = inference_api
@@ -71,6 +72,7 @@ class MetaReferenceAgentsImpl(Agents):
         self.safety_api = safety_api
         self.tool_runtime_api = tool_runtime_api
         self.tool_groups_api = tool_groups_api
+        self.telemetry_enabled = telemetry_enabled
 
         self.in_memory_store = InmemoryKVStoreImpl()
         self.openai_responses_impl: OpenAIResponsesImpl | None = None
@@ -135,6 +137,7 @@ class MetaReferenceAgentsImpl(Agents):
             ),
             created_at=agent_info.created_at,
             policy=self.policy,
+            telemetry_enabled=self.telemetry_enabled,
         )
 
     async def create_agent_session(