Add a data source with unstable ID and using Default/DefaultFunc

[paddycarver]

Reportedly you get a perma-diff if you use an unstable ID for a data source (see #1) and have a Default/DefaultFunc field set on the data source.

[kmoe]

Relevant: hashicorp/terraform-plugin-sdk#586

[bflad]

(Closing issues that likely won't get actioned anytime soon.) This is not an issue in terraform-plugin-framework. We can reopen if the external acceptance testing is required.

[github-actions]

I'm going to lock this issue because it has been closed for 30 days ⏳. This helps our maintainers find and focus on the active issues.
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