fix(settings): remove the switches that do nothing

Six settings had a control, a saved value, translated labels, and no reader
anywhere in the plugin. Flipping them changed a byte on disk and nothing else.

Three sat next to each other in the Chat tab under timestamps, so the section
read as four related options where only one -- the 24-hour clock -- works.
FormatTimestamp consults nothing else.

The first-run wizard offered one of them too, on its visual step, and listed it
back in the summary as if it had been applied. That is the first screen a new
user sees, so it goes as well.

Their own strings show how long this has been drifting: the wizard called
PrettierTimestamps "relative time", the settings tab called the same field
"modern layout". Two different features, one boolean, neither implemented. That
is also why these are removed rather than wired up -- there is no single
behaviour to restore, and inventing one belongs in a cycle that plans it.

Config fields stay, with a comment. A stored value should survive until the
rendering it describes exists, and dropping them would silently reset anyone who
set them.

Found by an audit that turned up considerably more of this: 433 of 824
translated resource keys reach no code at all, and the export, cleanup, tab
editor and pin paths are complete but unreachable. That is its own cycle; this
commit only clears what actively lies to the user in the window we are working
on.

HellionChat/Ui/Components/Settings/Tabs/ChatTab.cs

@@ -24,21 +24,6 @@ internal sealed class ChatTab
                 () => Plugin.Config.UseCompactDensity,
                 v => Plugin.Config.UseCompactDensity = v
             );
-            _w.Toggle(
-                "More compact pretty mode",
-                () => Plugin.Config.MoreCompactPretty,
-                v => Plugin.Config.MoreCompactPretty = v
-            );
-            _w.Toggle(
-                "Prettier timestamps",
-                () => Plugin.Config.PrettierTimestamps,
-                v => Plugin.Config.PrettierTimestamps = v
-            );
-            _w.Toggle(
-                "Hide same timestamps",
-                () => Plugin.Config.HideSameTimestamps,
-                v => Plugin.Config.HideSameTimestamps = v
-            );
             _w.Toggle(
                 "24-hour clock",
                 () => Plugin.Config.Use24HourClock,