Dedup command history by default (#17852)

Under ConPTY we don't load any user settings. `SetUpConsole` notes:
> If we are [ConPTY], we don't want to load any user settings,
> because that could result in some strange rendering results [...]

This enables deduplication by default, which I figured wouldn't cause
any regressions since it's a user-controllable setting anyway, while
it's clearly something the average user wants enabled, for the same
reason that PSReadLine has HistoryNoDuplicates enabled by default.

Closes #17797

## Validation Steps Performed
* Launch conhost, enter 2 commands, press F7, select the older one,
  press Enter, press F7. 2 entries ✅
* Launch WT, enter 2 commands, press F7, select the older one,
  press Enter, press F7. 2 entries ✅

src/host/settings.cpp

@@ -36,7 +36,7 @@ Settings::Settings() :
     _bAutoPosition(true),
     _uHistoryBufferSize(DEFAULT_NUMBER_OF_COMMANDS),
     _uNumberOfHistoryBuffers(DEFAULT_NUMBER_OF_BUFFERS),
-    _bHistoryNoDup(false),
+    _bHistoryNoDup(true),
     // ColorTable initialized below
     _uCodePage(ServiceLocator::LocateGlobals().uiOEMCP),
     _uScrollScale(1),
@@ -110,7 +110,7 @@ void Settings::ApplyDesktopSpecificDefaults()
     _bQuickEdit = TRUE;
     _uHistoryBufferSize = 50;
     _uNumberOfHistoryBuffers = 4;
-    _bHistoryNoDup = FALSE;
+    _bHistoryNoDup = true;
 
     _renderSettings.ResetColorTable();
 

src/propsheet/registry.cpp

@@ -79,7 +79,7 @@ VOID InitRegistryValues(
     pStateInfo->CursorSize = 25;
     pStateInfo->HistoryBufferSize = 25;
     pStateInfo->NumberOfHistoryBuffers = 4;
-    pStateInfo->HistoryNoDup = 0;
+    pStateInfo->HistoryNoDup = 1;
 
     // clang-format off
     if (pStateInfo->fIsV2Console)