Fix visibility of default LF parameters loader's constructor (#3164)

Signed-off-by: Hugo KULESZA <hugo.kulesza@rte-france.com>
(cherry picked from commit f1fadb9)

loadflow/loadflow-api/src/main/java/com/powsybl/loadflow/AbstractLoadFlowDefaultParametersLoader.java

@@ -18,7 +18,7 @@ public abstract class AbstractLoadFlowDefaultParametersLoader implements LoadFlo
     private final String name;
     private final String jsonParametersFile;
 
-    AbstractLoadFlowDefaultParametersLoader(String name, String jsonParametersFile) {
+    protected AbstractLoadFlowDefaultParametersLoader(String name, String jsonParametersFile) {
         this.name = Objects.requireNonNull(name);
         this.jsonParametersFile = Objects.requireNonNull(jsonParametersFile);
     }