Restore typehint but make it nullable #14350

Job	Run time
Core running from build / Core running from build / Linux	2m 27s
Core running from src / Core running from src / Windows	4m 22s
Core running from build / Core running from build / Windows	4m 6s
Core running from src / Core running from src / Linux	2m 0s
Core running from build / Core running from build / MacOS	3m 52s
Core running from src / Core running from src / MacOS	2m 7s
Gutenberg running from build / Gutenberg running from build / Linux	8m 46s
Gutenberg running from build / Gutenberg running from build / Windows	14m 8s
Gutenberg running from src / Gutenberg running from src / Linux	9m 1s
Gutenberg running from src / Gutenberg running from src / Windows	12m 39s
Gutenberg running from build / Gutenberg running from build / MacOS	10m 37s
Gutenberg running from src / Gutenberg running from src / MacOS	9m 52s
Slack Notifications	0s
Failed workflow tasks	0s
	1h 23m 57s

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