Update numeric conversion to fill NaN with 0 - see HEA-780

Ensure numeric conversion fills NaN values with 0.

Author: rhunwicks

pipelines/assets/livelihood_activity.py

@@ -1338,8 +1338,7 @@ def get_annotated_instances_from_dataframe(
         # Get the summary dataframe, grouped by strategy_type
         summary_df = pd.DataFrame(reported_summary_output.value["LivelihoodActivity"])
         for col in ["income", "expenditure", "kcals_consumed"]:
-            summary_df[col] = pd.to_numeric(summary_df[col], errors="coerce")
-
+            summary_df[col] = pd.to_numeric(summary_df[col], errors="coerce").fillna(0)
         summary_df = (
             summary_df[["strategy_type", "income", "expenditure", "kcals_consumed"]].groupby("strategy_type").sum()
         )