Revert operation string update in test

Author: tomvothecoder

tests/test_temporal.py

@@ -282,7 +282,7 @@ def test_weighted_annual_averages(self):
             },
             dims=["time", "lat", "lon"],
             attrs={
-                "operation": "temporal_averages",
+                "operation": "temporal_avg",
                 "mode": "group_average",
                 "freq": "year",
                 "weighted": "True",