Fix examples for JDK 21 (Android Studio Ladybug) #1915

Job	Run time
generator	5m 24s
init-script	3m 48s
flutter-integration-test (macos-13, 3.24.2)	10m 10s
flutter-integration-test (macos-13, 3.16.9)	11m 36s
lib (windows-2022, 3.5.2)	1m 55s
lib (windows-2022, 3.4.4)	1m 45s
flutter-integration-test (ubuntu-24.04, 3.24.2)	7m 39s
lib (windows-2022, 2.18.6)	2m 9s
flutter-integration-test (ubuntu-24.04, 3.16.9)	7m 39s
lib (macos-13, 3.5.2)	2m 53s
flutter-integration-test (windows-2022, 3.24.2)	7m 20s
lib (macos-13, 3.4.4)	2m 17s
flutter-integration-test (windows-2022, 3.16.9)	7m 44s
lib (macos-13, 2.18.6)	2m 56s
lib (ubuntu-24.04, 3.5.2)	1m 26s
lib (ubuntu-24.04, 3.4.4)	1m 29s
lib (ubuntu-24.04, 2.18.6)	1m 36s
	1h 19m 46s

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