GT911 driver : need a sleep() method to totally powered off the touch screen (like the GT911 driver used in Aruino IDE : TouchDrvGT911.hpp)

**Describe the problem you have/What new integration you would like**

**Please describe your use case for this integration and alternatives you've tried:**

**Additional context**

Hi !

I'm using the Lilygo EPD47 with the touchscreen.
In deep sleep, i've a 5.7mA power consumption : too high.

If i used the demo code and compile with Arduino IDE, the power in deep sleep is 380uA ... much better.

If i move all the C code (founded in demo code) used for the deepsleep in a Lambda, i'm stuck with the line making the touch screen sleeping : touch.sleep();
There's no sleep() method implemented in GT911 driver for ESPHOME

So, i think that in ESPHOME, the deep sleep of this board is not total for the touch screen.

In GT911 for Arduino it's :
```cpp
void sleep()
{
writeRegister(GT911_COMMAND, 0x05);
}

```

Is it possible to add this to the GT911 driver ?

Thanks.

Start by reading the GT911 driver and comparing it with the sleep implementation in TouchDrvGT911.hpp, focusing on the command sent to the controller. The work is done when the ESPHome GT911 driver exposes equivalent sleep behavior for deep sleep use; the issue mentions no test file or other entry point.

Written by the indexing model from the issue text.