outsidetempavg does not take negative values

[philsson]

From the HA logs

Logger: homeassistant.components.mqtt.number
Source: components/mqtt/number.py:184
integration: MQTT ([documentation](https://www.home-assistant.io/integrations/mqtt), [issues](https://github.com/home-assistant/core/issues?q=is%3Aissue+is%3Aopen+label%3A%22integration%3A+mqtt%22))
First occurred: December 31, 2024 at 3:58:33 PM (139 occurrences)
Last logged: January 2, 2025 at 10:47:16 PM

Invalid value for number.ebusd_basv_ebusd_basv_outsidetempavg_tempv: -7.25781 (range 0.0 - 100.0)
Invalid value for number.ebusd_basv_ebusd_basv_outsidetempavg_tempv: -7.46094 (range 0.0 - 100.0)
Invalid value for number.ebusd_basv_ebusd_basv_outsidetempavg_tempv: -7.67578 (range 0.0 - 100.0)
Invalid value for number.ebusd_basv_ebusd_basv_outsidetempavg_tempv: -7.86719 (range 0.0 - 100.0)
Invalid value for number.ebusd_basv_ebusd_basv_outsidetempavg_tempv: -8.02734 (range 0.0 - 100.0)