Fix federation provider example to load users file from it's own ClassLoader instead of Thread CL

examples/providers/federation-provider/src/main/java/org/keycloak/examples/federation/properties/ClasspathPropertiesFederationFactory.java

@@ -20,7 +20,7 @@ public class ClasspathPropertiesFederationFactory extends BasePropertiesFederati
     }
 
     protected InputStream getPropertiesFileStream(String path) {
-        InputStream is = Thread.currentThread().getContextClassLoader().getResourceAsStream(path);
+        InputStream is = getClass().getClassLoader().getResourceAsStream(path);
         if (is == null) {
             throw new IllegalStateException("Path not found for properties file");