Fix memory leak in waterworld_v4 by clearing old handlers before addi… #1113

Job	Run time
agilerl-tutorial-test (3.9, AgileRL)	17m 38s
agilerl-tutorial-test (3.10, AgileRL)	15m 27s
tutorial-test (3.8, Tianshou)	3m 22s
tutorial-test (3.8, CustomEnvironment)	39s
agilerl-tutorial-test (3.11, AgileRL)	17m 23s
tutorial-test (3.8, CleanRL)	6m 4s
tutorial-test (3.8, SB3/kaz)	4m 28s
tutorial-test (3.8, SB3/waterworld)	8m 27s
tutorial-test (3.8, SB3/connect_four)	3m 28s
tutorial-test (3.8, SB3/test)	2m 54s
tutorial-test (3.9, Tianshou)	2m 44s
tutorial-test (3.9, CustomEnvironment)	26s
tutorial-test (3.9, CleanRL)	6m 55s
tutorial-test (3.9, SB3/kaz)	4m 35s
tutorial-test (3.9, SB3/waterworld)	8m 18s
tutorial-test (3.9, SB3/connect_four)	2m 51s
tutorial-test (3.9, SB3/test)	2m 11s
tutorial-test (3.10, Tianshou)	4m 49s
tutorial-test (3.10, CustomEnvironment)	24s
tutorial-test (3.10, CleanRL)	7m 23s
tutorial-test (3.10, SB3/kaz)	6m 38s
tutorial-test (3.10, SB3/waterworld)	7m 58s
tutorial-test (3.10, SB3/connect_four)	2m 44s
tutorial-test (3.10, SB3/test)	2m 41s
tutorial-test (3.11, Tianshou)	2m 0s
tutorial-test (3.11, CustomEnvironment)	35s
tutorial-test (3.11, CleanRL)	7m 31s
tutorial-test (3.11, SB3/kaz)	4m 48s
tutorial-test (3.11, SB3/waterworld)	8m 46s
tutorial-test (3.11, SB3/connect_four)	2m 55s
tutorial-test (3.11, SB3/test)	2m 24s
	2h 49m 26s

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