chore: remove MangaGreat (EN)

dart/manga/multisrc/madara/sources.dart

@@ -260,8 +260,6 @@ List<Source> _madaraSourcesList =
           mangaclashSource,
           //MangaFreak.online (EN)
           mangafreakonlineSource,
-          //MangaGreat (EN)
-          mangagreatSource,
           //MangaKomi (EN)
           mangakomiSource,
           //MangaRead.org (EN)

dart/manga/multisrc/madara/src/en/mangagreat/mangagreat.dart

@@ -1,15 +0,0 @@
-import '../../../../../../../model/source.dart';
-
-Source get mangagreatSource => _mangagreatSource;
-
-Source _mangagreatSource = Source(
-  name: "MangaGreat",
-  baseUrl: "https://mangagreat.com",
-  lang: "en",
-
-  typeSource: "madara",
-  iconUrl:
-      "https://raw.githubusercontent.com/kodjodevf/mangayomi-extensions/$branchName/dart/manga/multisrc/madara/src/en/mangagreat/icon.png",
-  dateFormat: "MMMM dd, yyyy",
-  dateFormatLocale: "en_us",
-);