Set HVAC mode doesn't work if target mode is already current mode

[MinimalMule]

When trying to create automations I found that if you try to set the HVAC mode of an ITC to "off" when it is already "off" this can result in the ITC switching to auto.

[snowchaser75]

I'm also having this issue. I got around it by by checking the state of the ITC and only sending "off" if it wasn't already "off".

[sibowler]

I've also been having this issue. I think the fix is to change the climate.py file, line 210 from:
if hvac_mode == self.hvac_mode and hvac_mode != HVAC_MODE_OFF:
to
if hvac_mode == self.hvac_mode

so the block of code becomes:

async def async_set_hvac_mode(self, hvac_mode):
        """Set new target hvac mode."""
        if hvac_mode == self.hvac_mode:
            return
        elif hvac_mode == HVAC_MODE_OFF and self.hvac_mode != HVAC_MODE_OFF:
            await self._airtouch.request_group_power(self._id, POWER_OFF)
        else:
            await self._airtouch.request_group_power(self._id, POWER_ON)
        self.async_write_ha_state()

This seems to give the right behaviour, but still needs some more testing in case there's a scenario I've not thought of. There was likely a reason why the initial condition had that additional and hvac_mode != HVAC_MODE_OFF guard, but I can't see it. I've added some debug logging and am trialling, but @mihailescu2m if you could shed some light here, that would be appreciated :)