[Manager] Gray out projects in project wizard that are already attached #4953

Job	Run time
libs-build	5m 59s
apps-build	9m 37s
libs-cmake-build	6m 54s
client-armv6-build	3m 6s
client-arm-build	4m 27s
client-arm64-build	3m 10s
client-x86-build	3m 54s
client-x86_64-build	2m 58s
manager-build (assembleRelease)	4m 27s
manager-build (assembleXiaomi_release)	4m 34s
manager-build (assembleArmv6_release)	4m 30s
manager-build (jacocoTestReportDebug)	6m 23s
	59m 59s

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