Allow sht4x heater to be enabled/disabled during runtime

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

It would be nice if it were possible for the sht4x heater to be turned on/off during runtime (e.g. only turn the heater on when humidity is above say 90%) to avoid running the heater when there's no concern of condensation affecting humidity measurements.

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

I'm using the sensor in a weather station and I'd like to minimize wear and tear from running the heater in all conditions, and avoid potentially tainting temperature readings taken immediately after the heater runs.

**Additional context**

Start by locating the SHT4X integration and its heater configuration or control entry points. Determine how runtime enable/disable would be exposed and verify that the heater can be controlled conditionally while preserving the requested humidity and temperature measurement behavior.

Written by the indexing model from the issue text.