Update Quickstart for Flutter/Dart to v5 #317

Job	Run time
Lint	1m 18s
Run Unit Tests	1m 41s
Build Web	1m 57s
Build macOS Desktop	4m 53s
Build iOS	4m 29s
Build Android	6m 10s
Build Windows Desktop	3m 54s
BrowserStack iOS Testing	8m 27s
BrowserStack Android Testing	6m 46s
Test Summary	2s
	39m 37s

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