Always set/store the normalized sender address

The sender is also needed for encrypt to self.

GnuPG-bug-id: 5283

src/kleo/keyresolvercore.cpp

@@ -198,9 +198,7 @@ void KeyResolverCore::Private::setSender(const QString &address)
         return;
     }
     const auto normStr = QString::fromUtf8(normalized.c_str());
-    if (mSign) {
     mSender = normStr;
-    }
     addRecipients({address});
 }