[IMM32] ImeGetImeMenuItems is optional (reactos#8008)

Supporting old IMEs.
JIRA issue: CORE-19268
Do null check of ImeGetImeMenuItems
function of IME side, in
ImmGetImeMenuItemsAW function.

Author: katahiromz

dll/win32/imm32/imemenu.c

@@ -538,6 +538,15 @@ ImmGetImeMenuItemsAW(
         return 0;
     }
 
+    /* ImeGetImeMenuItems is optional */
+    if (!pImeDpi->ImeGetImeMenuItems)
+    {
+        WARN("ImeGetImeMenuItems is not available (optional).\n");
+        ImmUnlockImeDpi(pImeDpi);
+        ImmUnlockIMC(hIMC);
+        return 0;
+    }
+
     /* Is the IME ANSI? */
     BOOL bImcIsAnsi = Imm32IsImcAnsi(hIMC);