Tests: Rename some oEmbed test classes as per the naming conventions. #25596

Job	Run time
QUnit Tests / Run QUnit tests	2m 17s
Slack Notifications / Prepare notifications	3s
Slack Notifications / Success notifications	4s
Slack Notifications / Failure notifications	-1s
Slack Notifications / Cancelled notifications	-1s
Slack Notifications / Fixed notifications	-1s
Failed workflow tasks	0s
	2m 21s

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