The previous implementation was doing something weird when it was used during installation in:
verifySecurityAssessment(of: installedXcode)
.combineLatest(self.verifySigningCertificate(of: installedXcode.path.url))
It looks like it would subscribe after the Process.run future had already sent a value, and so it would never finish. This seems weird, and I'm assuming that I'm misunderstanding something about this behaviour, but dispatching manually seems reasonable and works.