fix(ui): clarify model defaults toast

[YUHAO-corn]

Summary

• replace the generic parameter recall toast used by the model default-settings action
• add a dedicated toast.modelDefaultsLoaded message so the success state reads clearly as Model Defaults Loaded

Fixes #6484.

Validation

• pnpm --dir invokeai/frontend/web exec prettier --check public/locales/en.json src/app/store/middleware/listenerMiddleware/listeners/setDefaultSettings.ts
• pnpm --dir invokeai/frontend/web exec eslint src/app/store/middleware/listenerMiddleware/listeners/setDefaultSettings.ts
• git diff --check

Review

• Independent agent review found no blocking issues and recommended merging.

[YUHAO-corn]

Hi maintainers, gentle follow-up here as well. This is a small copy/UX clarification and CI is green; happy to revise if there is a preferred wording or location for this message.