Fix tests

ml-agents/mlagents/trainers/stats.py

     std: float
     num: int
     sum: float
-    full_dist: np.array
+    full_dist: List[float]
-        return StatsSummary(
-            0.0, 0.0, 0, 0.0, np.zeros(1), StatsAggregationMethod.AVERAGE
-        )
+        return StatsSummary(0.0, 0.0, 0, 0.0, [0.0], StatsAggregationMethod.AVERAGE)
 
     @property
     def aggregated_value(self):
             )
             if key == "Environment/Cumulative Reward":
                 self.summary_writers[category].add_histogram(
-                    f"{key}_hist", value.full_dist, step
+                    f"{key}_hist", np.array(value.full_dist), step
                 )
             self.summary_writers[category].flush()
 
         if len(stat_values) == 0:
             return StatsSummary.empty()
 
-        if key == "Environment/Cumulative Reward":
-            full = np.array(stat_values)
-        else:
-            full = np.zeros(1)
-            full_dist=full,
+            full_dist=stat_values,
             aggregation_method=StatsReporter.stats_aggregation[self.category][key],
         )

ml-agents/mlagents/trainers/tests/test_agent_processor.py

             std=mock.ANY,
             num=2,
             sum=4.0,
+            full_dist=mock.ANY,
             aggregation_method=StatsAggregationMethod.AVERAGE,
         ),
         "most_recent": StatsSummary(
             sum=4.0,
+            full_dist=mock.ANY,
             aggregation_method=StatsAggregationMethod.MOST_RECENT,
         ),
         "summed": StatsSummary(
             sum=4.2,
+            full_dist=mock.ANY,
             aggregation_method=StatsAggregationMethod.SUM,
         ),
     }

ml-agents/mlagents/trainers/tests/test_stats.py

             std=1.0,
             num=1,
             sum=1.0,
+            full_dist=[0.0],
             aggregation_method=StatsAggregationMethod.AVERAGE,
         )
         tb_writer.write_stats("category1", {"key1": statssummary1}, 10)
         std=1.0,
         num=1,
         sum=1.0,
+        full_dist=[0.0],
         aggregation_method=StatsAggregationMethod.AVERAGE,
     )
     tb_writer.write_stats("category1", {"key1": statssummary1}, 10)
                 std=1.0,
                 num=1,
                 sum=1.0,
+                full_dist=[1.0],
                 aggregation_method=StatsAggregationMethod.AVERAGE,
             )
             console_writer.write_stats(
                 std=0.0,
                 num=1,
                 sum=0.0,
+                full_dist=[0.0],
                 aggregation_method=StatsAggregationMethod.AVERAGE,
             )
             console_writer.write_stats(
                 std=1.0,
                 num=1,
                 sum=1.0,
+                full_dist=[1.0],
                 aggregation_method=StatsAggregationMethod.AVERAGE,
             )
             console_writer.write_stats(