Reflect v1.6 interpolatable `import` ID

[radeksimko]

See hashicorp/terraform#33618

Currently we only assume the ID is a static string:

terraform-schema/internal/schema/1.5/import.go

Lines 24 to 28 in 8234469

	"id": {
	Constraint: schema.LiteralType{Type: cty.String},
	IsRequired: true,
	Description: lang.Markdown("ID of the resource to be imported. e.g. `i-abcd1234`"),
	},