added check (#1031)

* added  check

* blank line

* cleaner implementation

* check added

* tidied up

islandora.module

@@ -545,12 +545,11 @@ function islandora_entity_view(array &$build, EntityInterface $entity, EntityVie
   $route_match_item = \Drupal::routeMatch()->getParameters()->get($entity->getEntityTypeId());
   // Ensure the entity matches the route.
   if ($entity === $route_match_item) {
-    if ($display->getComponent('field_gemini_uri')) {
-      $mapper = \Drupal::service('islandora.entity_mapper');
-      $flysystem_config = Settings::get('flysystem');
-      $fedora_root = $flysystem_config['fedora']['config']['root'];
+    $flysystem_config = Settings::get('flysystem');
+    $fedora_root = $flysystem_config['fedora']['config']['root'] ?? NULL;
+    if ($display->getComponent('field_gemini_uri') && $fedora_root) {
       $fedora_root = rtrim($fedora_root, '/');
-
+      $mapper = \Drupal::service('islandora.entity_mapper');
       if ($entity->getEntityTypeId() == 'media') {
         // Check if the source file is in Fedora or not.
         $media_source_service = \Drupal::service('islandora.media_source_service');