BedJet - shutoff time support

**Describe the problem you have/What new integration you would like**
The BedJet remote control and app allow setting an amount of time before the unit shuts itself off. This defaults to half an hour in heat mode and 10 hours in cool mode. I'd like to be able to set that via the ESPHome BedJet integration as well.

**Please describe your use case for this integration and alternatives you've tried:**
Right now when I turn my BedJet on to heat mode it automatically shuts off after half an hour. I'd like to be able to have it stay on for longer periods than that.

I can sort of work around this by setting up an automation that runs once every half hour plus a few seconds that turns the BedJet back on, but that's a pain.

**Additional context**

Love the BedJet integration otherwise. Thank you @jhansche!