fleetctl gitops should explicitly set MDM configs if not defined

[getvictor]

Fleet version:
4.45.0
Web browser and operating system:

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💥  Actual behavior

Not setting enable_disk_encryption in YAML caused the encryption profile to remain on DB instead of being cleared.

🧑‍💻  Steps to reproduce

See #16636

🕯️ More info (optional)

N/A

🛠️ To fix

fleetctl gitops should explicitly set unset MDM settings to default values to prevent potential configuration surprises.

[fleet-release]

I couldn't think of a haiku this time. (See fleetdm.com logs for more information.)