chore(deps): update embroider monorepo to v4 (major)

[renovate[bot]]

This PR contains the following updates:

Package	Change	Age	Adoption	Passing	Confidence
@embroider/test-setup (source)	3.0.3 -> 4.0.0
@embroider/webpack (source)	3.2.3 -> 4.0.8

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