Fix overriding deprecated method of NumberEntity

[HepoH3]

Currently there is a warning:

custom_components.xiaomi_gateway3.number::XiaomiNumber is overriding deprecated methods on an instance of NumberEntity, this is not valid and will be unsupported from Home Assistant 2022.10

This change fix warning, but I'm a bit of confused because the old method is not explicitly used anywhere, so I changed the override only.

For now everything works smooth on my setup.

Fix: #777, #780.

[AlexxIT]

This change will break backward compatibility of many Hass versions. I can't accept it

[HepoH3]

You mean integration will stop working on some installation with HA core older some version?

[AlexxIT]

Yes. All 2022 won't work

[HepoH3]

I got you, no problem — it can wait if you don't mind.

[AlexxIT]

Thanks! I'll add backward compatibility