Issue #3436993 stager exceptions handling

Closes #3436993

automatic_updates_extensions/tests/src/Functional/ComposerStagerOperationFailureTest.php

@@ -42,6 +42,7 @@ class ComposerStagerOperationFailureTest extends UpdaterFormTestBase {
       '8.1.0',
       '8.1.1',
     );
+    $this->getStageFixtureManipulator()->setVersion('drupal/semver_test', '8.1.1');
     $this->assertUpdatesCount(1);
     $page->checkField('projects[semver_test]');