livekit: wait for disconnect before callback #1145

Job	Run time
Build (x86_64-pc-windows-msvc)	6m 36s
Build (aarch64-pc-windows-msvc)	6m 19s
Build (x86_64-apple-darwin)	5m 13s
Build (aarch64-apple-darwin)	5m 15s
Build (aarch64-apple-ios)	5m 33s
Build (aarch64-apple-ios-sim)	5m 7s
Build (x86_64-unknown-linux-gnu)	3m 55s
Build (aarch64-unknown-linux-gnu)	5m 44s
Build (aarch64-linux-android)	3m 34s
Build (armv7-linux-androideabi)	3m 27s
Build (x86_64-linux-android)	3m 51s
	54m 34s

Provide feedback