fix: fix custom form empty dropdown crash #4361

Job	Run time
build (server, debug, true, true)	5m 44s
build (server, debug, true, false)	5m 35s
build (server, debug, false, true)	4m 41s
build (server, debug, false, false)	4m 34s
build (server, release, true, true)	5m 42s
build (server, release, true, false)	4m 53s
build (server, release, false, true)	4m 1s
build (server, release, false, false)	5m 3s
build (client, debug, true, true)	4m 49s
build (client, debug, true, false)	2m 57s
build (client, debug, false, true)	3m 0s
build (client, debug, false, false)	3m 37s
build (client, release, true, true)	5m 3s
build (client, release, true, false)	5m 28s
build (client, release, false, true)	4m 44s
build (client, release, false, false)	5m 13s
	1h 15m 4s

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