feat: Accessible resize handles with keyboard activation (separator toggle) #4875

Job	Run time
dry-run / Build jest-preset	22s
dry-run / Build browser-test-tools	2m 32s
dry-run / Build collection-hooks	1m 12s
dry-run / Build documenter	2m 11s
dry-run / Build global-styles	24s
dry-run / Build test-utils	1m 4s
dry-run / Build component-toolkit	1m 23s
dry-run / Build theming-core	57s
dry-run / Build components	4m 28s
dry-run / Components unit tests	7m 25s
dry-run / Build board components	3m 47s
dry-run / Components integration tests	16m 36s
dry-run / Components accessibility tests shard (1)	1m 6s
dry-run / Components accessibility tests shard (2)	11m 13s
dry-run / Components accessibility tests shard (3)	11m 16s
dry-run / Components accessibility tests shard (4)	54s
dry-run / Components accessibility tests shard (5)	11m 30s
dry-run / Components accessibility tests shard (6)	11m 30s
dry-run / Demos tests	12m 45s
dry-run / Components accessibility tests	0s
	1h 42m 35s

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