Fix quote block font-weight inconsistency in Twenty Twenty theme #12969

Job	Run time
Core running from build / Core running from build / Linux	2m 9s
Core running from src / Core running from src / Linux	2m 2s
Core running from src / Core running from src / Windows	3m 53s
Core running from build / Core running from build / MacOS	1m 51s
Core running from build / Core running from build / Windows	3m 15s
Core running from src / Core running from src / MacOS	2m 59s
Gutenberg running from build / Gutenberg running from build / Linux	8m 33s
Gutenberg running from src / Gutenberg running from src / Linux	8m 19s
Gutenberg running from build / Gutenberg running from build / Windows	11m 56s
Gutenberg running from src / Gutenberg running from src / Windows	12m 47s
Gutenberg running from build / Gutenberg running from build / MacOS	8m 18s
Gutenberg running from src / Gutenberg running from src / MacOS	8m 2s
Slack Notifications	0s
Failed workflow tasks	0s
	1h 14m 4s

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