Include 'id' in datastore read

The datastore 'id' returned in the datastore read
response should be the same as the 'id' used in the
GET request. Nevertheless we use the returned value,
mainly to detect the extremely unlikely case where
the API returns an unexpected 'id' value.

internal/resources/datastore/resource.go

@@ -147,6 +147,18 @@ func doRead(
 		return
 	}
 
+	id := datastore.GetId()
+	if id == nil {
+		(*diagsP).AddError(
+			"error reading datastore",
+			"'id' is nil",
+		)
+
+		return
+	}
+
+	(*dataP).Id = types.StringValue(*id)
+
 	datastoreName := datastore.GetName()
 	if datastoreName == nil {
 		(*diagsP).AddError(