Series import: IllegalArgumentException when only price and currency were extracted

[php-coder]

Series import fails when only price/currency were extracted.

Log:

2020-01-15 22:30:34.676 [user:1 ] INFO 61320 --- [qtp307894016-20] r.m.w.f.s.i.SeriesImportServiceImpl : Request # 1: page were parsed (AddSeriesParsedDataDbDto(...), SeriesSalesParsedDataDbDto(sellerId=null, sellerGroupId=null, sellerName=null, sellerUrl=null, price=660.00, currency=RUB))

Exception:

...
Caused by: java.lang.IllegalArgumentException: Seller id must be non null
	at org.apache.commons.lang3.Validate.isTrue(Validate.java:158) ~[commons-lang3-3.8.jar:3.8]
	at ru.mystamps.web.feature.series.sale.SeriesSalesServiceImpl.add(SeriesSalesServiceImpl.java:40) ~[classes/:na]
...

[php-coder]

It seems like this happens because 1) seller-related fields weren't shown while they should (#1232) and 2) we don't have validation here that prevents this on controller-level (#859)

[php-coder]

After fixing #1232 it's hard or nearly impossible to reproduce this issue: the fields for name/url are shown on the page and after form submission they have empty values. Because of that, a participant is created (yes, with empty name, url) and hence sellerId isn't null now.

But after fixing #851 and #854 it should become reproducible again.

[php-coder]

But after fixing #851 and #854 it should become reproducible again.

The exception is different this time:

Caused by: java.lang.IllegalArgumentException: Name must be non null
	at org.apache.commons.lang3.Validate.isTrue(Validate.java:158) ~[commons-lang3-3.8.jar:3.8]
	at ru.mystamps.web.feature.participant.ParticipantServiceImpl.add(ParticipantServiceImpl.java:42) ~[classes/:na]