Remove rounding of temperature reading

[hthiery]

With homeassistant 0.65.0 the filter sensor is introduced. Now there
is a common way to filter the peaks comming from the readings.

Checklist:

• The code change is tested and works locally.

If the code does not interact with devices:

• Local tests with tox run successfully. Your PR cannot be merged unless tests pass
• Tests have been added to verify that the new code works.

[arsaboo]

The filter sensor is not solving the temperature rounding problem. We probably still need the rounding so that it appears properly in the frontend.

[hthiery]

I just used the rounding here to minimize the hight jitter around the themperature readings. E.g. it was often observed that the reading value changed from one to another value and back every state update. I hoped to fix this with the filter sensor.

My workaround with round was just to reduce this behavior, but it was still present on the 0.5 to 0.6 step and at 0.9 to 1.0... so this workaround reduced the resolution from 0.1 steps to 0.5 steps what is a limitaion.

[balloob]

That's good that we have removed this. We shouldn't have merged this to begin with. It's important that integration of devices show the raw API data. It's indeed up to 2nd order things, like the filter sensor, to smooth it out.