Fixes #3127: Non-interactive invoke via 'drush @alias cmd' (#3407)

* Fixes #3127: Non-interactive invoke via 'drush @alias cmd'

* Always use 'interactive' mode when redispatching (yes, even in 'non-interactive' mode, sigh).

src/Runtime/RedispatchHook.php

@@ -85,13 +85,14 @@ public function redispatch(InputInterface $input)
         // in $redispatchArgs.
         $redispatchOptions = [];
 
+        // n.b. Defining the 'backend' flag here causes failed execution in the
+        // non-interactive case, even if 'backend' is set to 'false'.
         $backend_options = [
             'drush-script' => $this->getConfig()->get('paths.drush-script', null),
             'remote-host' => $remote_host,
             'remote-user' => $remote_user,
             'additional-global-options' => [],
-            'integrate' => true,
-            'backend' => false,
+            'interactive' => true,
         ];
         if ($input->isInteractive()) {
             $backend_options['#tty'] = true;