google_dns_managed_zone: add zone ID attribute

[modular-magician]

In the data source for DNS managed zones, include a new "managed_zone_id" attribute reporting the zone's ID, matching the corresponding google_dns_managed_zone resource's output attribute with the same name.

While we're here, revise the order in which we transcribe the fields from the fetched object to the data source's attributes to match the declaration order in the schema.

Supersedes hashicorp/terraform-provider-google#12301.
Relates to #6186.
Fixes hashicorp/terraform-provider-google#7128.

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dns: added `managed_zone_id` attribute to `google_dns_managed_zone` data source

Derived from GoogleCloudPlatform/magic-modules#6406