chore: internal change, make Model.provider_model_id non-optional (#2690)

- POST /v1/models accepts optional provider_model_id
- ModelsRoutingTable.register_model handler ensures it is non-None,
providing a default

usage of Model.provider_model_id will no longer need to detect None

llama_stack/apis/models/models.py

@@ -7,7 +7,7 @@
 from enum import StrEnum
 from typing import Any, Literal, Protocol, runtime_checkable
 
-from pydantic import BaseModel, ConfigDict, Field
+from pydantic import BaseModel, ConfigDict, Field, field_validator
 
 from llama_stack.apis.resource import Resource, ResourceType
 from llama_stack.providers.utils.telemetry.trace_protocol import trace_protocol
@@ -36,13 +36,21 @@ class Model(CommonModelFields, Resource):
         return self.identifier
 
     @property
-    def provider_model_id(self) -> str | None:
+    def provider_model_id(self) -> str:
+        assert self.provider_resource_id is not None, "Provider resource ID must be set"
         return self.provider_resource_id
 
     model_config = ConfigDict(protected_namespaces=())
 
     model_type: ModelType = Field(default=ModelType.llm)
 
+    @field_validator("provider_resource_id")
+    @classmethod
+    def validate_provider_resource_id(cls, v):
+        if v is None:
+            raise ValueError("provider_resource_id cannot be None")
+        return v
+
 
 class ModelInput(CommonModelFields):
     model_id: str