chore: deprecate /v1/inspect/providers (#1678)

# What does this PR do?

with the new /v1/providers API, /v1/inspect/providers is duplicative,
deprecate it by removing the route, and add a test for the full
/v1/providers API

resolves #1623 

## Test Plan

`uv run pytest -v tests/integration/providers --stack-config=ollama
--text-model="meta-llama/Llama-3.2-3B-Instruct"
--embedding-model=all-MiniLM-L6-v2`

<img width="1512" alt="Screenshot 2025-03-18 at 9 18 38 AM"
src="https://github.com/user-attachments/assets/2db30f25-3ff6-4374-b39d-0047f093fe36"
/>

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

llama_stack/apis/inspect/inspect.py

@@ -24,17 +24,6 @@ class HealthInfo(BaseModel):
     # TODO: add a provider level status
 
 
-@json_schema_type
-class ProviderInfo(BaseModel):
-    api: str
-    provider_id: str
-    provider_type: str
-
-
-class ListProvidersResponse(BaseModel):
-    data: List[ProviderInfo]
-
-
 @json_schema_type
 class VersionInfo(BaseModel):
     version: str
@@ -46,9 +35,6 @@ class ListRoutesResponse(BaseModel):
 
 @runtime_checkable
 class Inspect(Protocol):
-    @webmethod(route="/inspect/providers", method="GET")
-    async def list_providers(self) -> ListProvidersResponse: ...
-
     @webmethod(route="/inspect/routes", method="GET")
     async def list_routes(self) -> ListRoutesResponse: ...
 

llama_stack/distribution/inspect.py

@@ -11,9 +11,7 @@ from pydantic import BaseModel
 from llama_stack.apis.inspect import (
     HealthInfo,
     Inspect,
-    ListProvidersResponse,
     ListRoutesResponse,
-    ProviderInfo,
     RouteInfo,
     VersionInfo,
 )
@@ -39,24 +37,6 @@ class DistributionInspectImpl(Inspect):
     async def initialize(self) -> None:
         pass
 
-    async def list_providers(self) -> ListProvidersResponse:
-        run_config = self.config.run_config
-
-        ret = []
-        for api, providers in run_config.providers.items():
-            ret.extend(
-                [
-                    ProviderInfo(
-                        api=api,
-                        provider_id=p.provider_id,
-                        provider_type=p.provider_type,
-                    )
-                    for p in providers
-                ]
-            )
-
-        return ListProvidersResponse(data=ret)
-
     async def list_routes(self) -> ListRoutesResponse:
         run_config = self.config.run_config