Generation data being collected when it falls below 0kw

[ADIMANV]

Describe the bug

The data being collected from the SLDC website provided some faulty data. The data contained negative generation, which caused the error calculations for September to be a very high negative percentage. A fix in the backend should be implemented to ignore numbers that are below 0 kW so that our calculations are intact.
This issue is similar to : openclimatefix/ruvnl-consumer-app#20

Expected behavior

The generation data that is seen above where they cross the 0 kW threshold should be completely ignored.