Wire with_remote_overrides to construct model families (#7621)

- This PR wires `with_remote_overrides` and make the
`construct_model_families` an async function
- Moves getting model family a level above to keep the function `sync`
- Updates the tests to local, offline, and `sync` helper for model
families

codex-rs/core/tests/suite/client.rs

@@ -1015,11 +1015,9 @@ async fn azure_responses_request_includes_store_and_reasoning_ids() {
     let effort = config.model_reasoning_effort;
     let summary = config.model_reasoning_summary;
     let config = Arc::new(config);
-
+    let model_family = ModelsManager::construct_model_family_offline(&config.model, &config);
     let conversation_id = ConversationId::new();
     let auth_manager = AuthManager::from_auth_for_testing(CodexAuth::from_api_key("Test API Key"));
-    let models_manager = Arc::new(ModelsManager::new(auth_manager.clone()));
-    let model_family = models_manager.construct_model_family(&config.model, &config);
     let otel_event_manager = OtelEventManager::new(
         conversation_id,
         config.model.as_str(),

codex-rs/core/tests/suite/prompt_caching.rs

@@ -137,6 +137,7 @@ async fn prompt_tools_are_consistent_across_requests() -> anyhow::Result<()> {
     let base_instructions = conversation_manager
         .get_models_manager()
         .construct_model_family(&config.model, &config)
+        .await
         .base_instructions
         .clone();