Fix import of CustomerTaxGroup inside models
Fix import of CustomerTaxGroup inside models

Should import from a submodule to avoid circular imports.

suutari-ai/shoop,taedori81/shoop,shoopio/shoop,taedori81/shoop,suutari/shoop,shawnadelic/shuup,suutari/shoop,akx/shoop,taedori81/shoop,shoopio/shoop,akx/shoop,suutari-ai/shoop,hrayr-artunyan/shuup,suutari-ai/shoop,shoopio/shoop,hrayr-artunyan/shuup,akx/shoop,hrayr-artunyan/shuup,shawnadelic/shuup,shawnadelic/shuup,suutari/shoop