Use RenderSettings for DECSET 2026 - Synchronized Output

[lhecker]

RenderSettings already stores DECSCNM (reversed screen),
so it only makes sense to also store DECSET 2026 there.

Validation Steps Performed

• Same as in Implement DECSET 2026 - Synchronized Output #18826 ✅

[j4james]

Still needs to be reset here:

diff --git a/src/renderer/base/RenderSettings.cpp b/src/renderer/base/RenderSettings.cpp
index 371b591b3..2e8ae8d0c 100644
--- a/src/renderer/base/RenderSettings.cpp
+++ b/src/renderer/base/RenderSettings.cpp
@@ -46,9 +46,9 @@ void RenderSettings::RestoreDefaultSettings() noexcept
 {
     _colorTable = _defaultColorTable;
     _colorAliasIndices = _defaultColorAliasIndices;
-    // For now, DECSCNM is the only render mode we need to reset. The others are
-    // all user preferences that can't be changed programmatically.
-    _renderMode.reset(Mode::ScreenReversed);
+    // DECSCNM and Synchronized Output are the only render modes we need to reset.
+    // The others are all user preferences that can't be changed programmatically.
+    _renderMode.reset(Mode::ScreenReversed, Mode::SynchronizedOutput);
 }
 
 // Routine Description:

I know this is unlikely to effect most people, but it matters to me because it causes Windows Terminal to register a failure in one of my test frameworks when verifying RIS correctness.

[lhecker]

Ah thanks, I forgot about RIS.

[j4james]

LGTM