Fix computation of metric distance_traveled

Author: MichaelSchuldes

omega_prime/metrics.py

@@ -91,9 +91,9 @@ def distance_traveled(df) -> tuple[pl.DataFrame, dict[str, pl.DataFrame]]:
     return df.with_columns(
         (pl.col("x").diff() ** 2 + pl.col("y").diff() ** 2)
         .sqrt()
-        .over("idx")
         .fill_null(0.0)
         .cum_sum()
+        .over("idx", order_by='total_nanos')
         .alias("distance_traveled"),
     ), {}