Disable Realbooru while API is offline

test/backend/isar_integration_test.dart

@@ -74,6 +74,10 @@ void main() {
       'e926',
       'realbooru',
     ]);
+    expect(
+      providers.singleWhere((provider) => provider.id == 'realbooru').enabled,
+      isFalse,
+    );
   });
 
   test('settings saveEnabledProviders updates provider configs', () async {

test/backend/provider_parser_test.dart

@@ -210,7 +210,7 @@ void main() {
         .where((provider) => provider.id == 'realbooru')
         .single;
 
-    expect(realbooru.enabled, isTrue);
+    expect(realbooru.enabled, isFalse);
     expect(realbooru.apiType, 'realbooru');
     expect(realbooru.baseUrl, 'https://realbooru.com');
   });