chore: improve error handling during widget disposal on example app #713

Job	Run time
Run iOS native unit tests	4m 21s
Run dart unit tests	1m 6s
Run Android native unit tests	8m 13s
Build iOS	5m 10s
Build Android	8m 41s
Run iOS Integration Tests	15m 17s
Run Android Integration Tests	18m 39s
Run dart unit tests	1m 6s
Run iOS native unit tests	4m 21s
Run Android native unit tests	8m 13s
Run iOS Integration Tests	16m 52s
Build iOS	5m 10s
Build Android	8m 41s
Run Android Integration Tests	18m 39s
	2h 4m 29s

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