Change camera exposure step to integer #1122

Job	Run time
Build Examples	4m 32s
PhotonClient Build	40s
Gradle Build	4m 48s
Build Offline Docs	48s
Photonlib - Build Docker - Athena	7m 44s
Photonlib - Build Host - Win64	8m 23s
Photonlib - Build Docker - Raspbian	8m 4s
Photonlib - Build Host - macOS	8m 8s
Photonlib - Build Docker - Aarch64	9m 3s
Photonlib - Build Host - Linux	4m 40s
Build fat JAR - Win64	1m 56s
Build fat JAR - macOS	2m 3s
Build fat JAR - Linux	1m 34s
Build fat JAR - macOSArm	2m 7s
Build fat JAR - LinuxArm32	1m 20s
Build fat JAR - LinuxArm64	1m 26s
smoketest-RaspberryPi	1m 6s
run-smoketest-native (ubuntu-latest, jar-Linux, -Djdk.lang.Process.launchMechanism=vfork)	56s
Build image - ${{ matrix.image_url }}	0s
run-smoketest-native (windows-latest, jar-Win64)	28s
run-smoketest-native (macos-latest, jar-macOS, x64)	26s
release	0s
	1h 10m 12s

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