It's highly unlikely that Estring would cause liver damage, so no, you needn't be concerned. Estring releases estrogen locally, in the vagina; this is not metabolized through the liver. We do know that women with significant liver disease are not good candidates for oral estrogen, which is metabolized through the liver.
The warning label you read is required by the FDA for all estrogen products, even though the same risks are not posed for all forms. There's a request pending with the FDA to change this "class labeling" to be less confusing.
In the meantime, your history is not a reason to avoid a localized estrogen product.