fix(gemini): check if json can be decoded (#446)

Signed-off-by: Aaron Pham <contact@aarnphm.xyz>

lua/avante/sidebar.lua

@@ -1383,7 +1383,7 @@ function Sidebar:create_input()
     if self:get_layout() == "vertical" then
       return "bottom"
     end
-    return "right"
+    return Config.windows.direction
   end
 
   local get_size = function()