feat: enable `embroider-optimized` scenario #14448

Job	Run time
Get files changed and conditionally skip CI	14s
Tests	6m 14s
ember-lts-3.28	37s
ember-lts-4.12	39s
ember-beta	35s
embroider-safe	2m 57s
embroider-optimized	1m 21s
	12m 37s

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