fix(privacy): the header gave away what the log was hiding

Screenshot mode anonymises sender names in the message list. The channel header
I added yesterday sat above that list and showed two things it should not.

The home world, on the right. It narrows a player down almost as far as the
character name does, and the mode exists so a picture can be shared.

Worse, the tab name on the left. AutoTellTabsService builds a tell tab's name as
"Player@World", so a tell conversation had the partner's name and world set in
tracked caps directly above a log where every message had been anonymised. The
one place a reader looks first was the one place still naming them.

The name is suppressed only where it actually names someone -- a tab with a tell
target set. General or Trade stay readable, because they identify nobody, and a
self-named tab is the user's own text.

Found by asking what the new surface shows rather than by a test failing. Nothing
here was failing.

HellionChat/Ui/Windows/WidgetGalleryWindow.cs

@@ -96,7 +96,8 @@ internal sealed class WidgetGalleryWindow : Window
             _headerLoggedOut ? null : "Ravana",
             DateTimeOffset.Now,
             Plugin.Config.Use24HourClock,
-            Resources.HellionStrings.ChannelHeader_NotLoggedIn
+            Resources.HellionStrings.ChannelHeader_NotLoggedIn,
+            Plugin.Config.ScreenshotMode
         );
 
         ChannelHeader.Draw(_headerSample, mode, fonts, detail, 0f);