Add blocker for an invalid Imunify license

[cPholloway]

Case RE-373: If a server has an invalid Imunify license, then the Imunify component can fail in expected ways. This can further lead to the elevate script failing in stage 4 due to the Imunify post_leapp component failing and the EA4 component relying on the Imunify component to succeed.

Changelog: Add blocker for an invalid Imunify license

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