Fix generics in EppXmlTransformer.unmarshal to not be only on the return type.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=124914271

javatests/google/registry/flows/EppToolActionTest.java

@@ -12,7 +12,6 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-
 package google.registry.flows;
 
 import static com.google.common.truth.Truth.assertThat;