conpty: request DSR-CPR before Win32 input mode (microsoft#16445)

This prevents an issue in conhost where older versions of Windows
Terminal (including the ones currently inbox in Windows, as well as
stable and preview) will *still* cause WSL interop to hang on startup.

Since VT input is erroneously re-encoded as Win32 input events on those
versions, we need to make sure we request the cursor position *before*
enabling Win32 input mode. That way, the CPR we get back is properly
encoded.

Author: DHowett

src/host/VtIo.cpp

@@ -263,12 +263,6 @@ bool VtIo::IsUsingVt() const
         CATCH_RETURN();
     }
 
-    // GH#4999 - Send a sequence to the connected terminal to request
-    // win32-input-mode from them. This will enable the connected terminal to
-    // send us full INPUT_RECORDs as input. If the terminal doesn't understand
-    // this sequence, it'll just ignore it.
-    LOG_IF_FAILED(_pVtRenderEngine->RequestWin32Input());
-
     // MSFT: 15813316
     // If the terminal application wants us to inherit the cursor position,
     //  we're going to emit a VT sequence to ask for the cursor position, then
@@ -287,6 +281,12 @@ bool VtIo::IsUsingVt() const
         }
     }
 
+    // GH#4999 - Send a sequence to the connected terminal to request
+    // win32-input-mode from them. This will enable the connected terminal to
+    // send us full INPUT_RECORDs as input. If the terminal doesn't understand
+    // this sequence, it'll just ignore it.
+    LOG_IF_FAILED(_pVtRenderEngine->RequestWin32Input());
+
     if (_pVtInputThread)
     {
         LOG_IF_FAILED(_pVtInputThread->Start());