[NTUSER] IntLanguageToggle(): Guard against NULL pFocusQueue (reactos#8368)

Addendum to commit 25b7447 (PR reactos#5839)

Author: HBelusca

win32ss/user/ntuser/keyboard.c

@@ -821,12 +821,17 @@ IntLanguageToggle(
     _In_ BOOL bSameLang,
     _In_ INT nKeyState)
 {
-    PWND pWnd = pFocusQueue->spwndFocus;
-    HWND hWnd;
-    WPARAM wParam = 0;
+    PWND pWnd;
     PTHREADINFO pti;
     PKL pkl;
+    WPARAM wParam = 0;
 
+    if (!pFocusQueue)
+    {
+        ERR("IntLanguageToggle(): NULL pFocusQueue\n");
+        return;
+    }
+    pWnd = pFocusQueue->spwndFocus;
     if (!pWnd)
         pWnd = pFocusQueue->spwndActive;
     if (!pWnd)
@@ -843,8 +848,7 @@ IntLanguageToggle(
     if (gSystemFS & pkl->dwFontSigs)
         wParam |= INPUTLANGCHANGE_SYSCHARSET;
 
-    hWnd = UserHMGetHandle(pWnd);
-    UserPostMessage(hWnd, WM_INPUTLANGCHANGEREQUEST, wParam, (LPARAM)pkl->hkl);
+    UserPostMessage(UserHMGetHandle(pWnd), WM_INPUTLANGCHANGEREQUEST, wParam, (LPARAM)pkl->hkl);
 }
 
 /* Check Language Toggle by [Left Alt]+Shift or Ctrl+Shift */