add close method to AudioSource and VideoSource #343

Job	Run time
REUSE-3.2	15s
Formatting	19s
Check for changes	7s
Test (18)	17s
Test (20)	14s
Test (22)	19s
Test (latest)	18s
stable - x86_64-apple-darwin - node@20	6m 57s
stable - aarch64-apple-darwin - node@20	4m 58s
stable - x86_64-pc-windows-msvc - node@20	12m 5s
stable - x86_64-unknown-linux-gnu - node@20	6m 40s
stable - aarch64-unknown-linux-gnu - node@20	10m 42s
Release	0s
	43m 11s

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