Make missing password and error

If the URL is set but no password
this is clearly a config error.

(cherry picked from commit 184a8b2)

extensions/vertx-http/deployment/src/main/java/io/quarkus/vertx/http/deployment/devmode/HttpRemoteDevClientProvider.java

@@ -28,9 +28,8 @@ public Optional<RemoteDevClient> getClient() {
             return Optional.empty();
         }
         if (!liveReloadConfig.password.isPresent()) {
-            log.warn(
+            throw new RuntimeException(
                     "Live reload URL set but no password, remote dev requires a password, set quarkus.live-reload.password on both server and client");
-            return Optional.empty();
         }
         return Optional.of(new HttpRemoteDevClient(liveReloadConfig.url.get(), liveReloadConfig.password.get()));
     }