Fix wrong import

[balloob]

I am not sure why this was a warning and not an error. Probably because it was in JS.

Noticed in webpack build:

    WARNING in ./src/panels/lovelace/components/hui-entities-toggle.js 52:4-21
    "export 'default' (imported as 'turnOnOffEntities') was not found in '../common/entity/turn-on-off-entities'
     @ ./src/panels/lovelace/cards/hui-entities-card.ts
     @ ./src/panels/lovelace/hui-unused-entities.js
     @ ./src/panels/lovelace/hui-root.js
     @ ./src/panels/lovelace/ha-panel-lovelace.js
     @ ./src/layouts/partial-panel-resolver.js
     @ ./src/layouts/home-assistant-main.js
     @ ./src/layouts/app/home-assistant.js
     @ ./src/entrypoints/app.js