Build/Test Tools: Fix group for `wp_unique_prefixed_id()` tests. #25950

Job	Run time
E2E Tests with SCRIPT_DEBUG enabled	6m 39s
E2E Tests with SCRIPT_DEBUG disabled	5m 45s
Slack Notifications / Prepare notifications	5s
Slack Notifications / Cancelled notifications	0s
Slack Notifications / Success notifications	2s
Slack Notifications / Failure notifications	0s
Slack Notifications / Fixed notifications	0s
Failed workflow tasks	0s
	12m 31s

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