Specifying the hostedZoneRole does not work with mint mode

We need to add similar validation to this:

https://github.com/openshift/installer/commit/2f93c420ca10ad867a5564e272f06a91e4eef41f

Acceptance Criteria:

Description of criteria:

• Validation should throw an error when installconfig.CredentialsMode is not set to either Manual or Passthrough and installconfig.aws.platform.hostedZoneRole != ""

(optional) Out of Scope:

Detail about what is specifically not being delivered in the story

Engineering Details:

• (optional) https://github/com/link.to.enhancement/
• (optional) https://issues.redhat.com/link.to.spike
• Engineering detail 1
• Engineering detail 2

This requires/does not require a design proposal.
This requires/does not require a feature gate.