Don't load a series comment for anonymous users

[0pdd]

The puzzle 1505-6101f84e from #1505 has to be resolved:

mystamps/src/main/java/ru/mystamps/web/feature/series/SeriesServiceImpl.java

Line 317 in 32c612c

Validate.isTrue(seriesId != null, "Series id must be non null");

The puzzle was created by Slava Semushin on 31-Jan-21.