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 https://github.com/fleetdm/fleet/issues/16636

🕯️ More info (optional)

N/A

🛠️ To fix

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