TF-1808: Hanlde store email when opening email

(cherry picked from commit 2c895379f83b34e9bafb7545b21d790d01d444af)

core/test/utils/file_utils_test.dart

@@ -30,7 +30,7 @@ void main() {
       /// Create a temporary file that will be deleted after `getFromFile` is done
       final file = await FileUtils().saveToFile(nameFile: fileName, content: fileContent);
 
-      final htmlString = await FileUtils().getFromFile(nameFile: fileName);
+      final htmlString = await FileUtils().getContentFromFile(nameFile: fileName);
 
       expect(htmlString.isNotEmpty, equals(true));