fix: .ncs will now show an error if setting a pixel fails

src/NadekoBot/data/strings/responses/responses.en-US.json

@@ -1109,6 +1109,7 @@
   "invalid_color": "Color you've specified is invalid.",
   "nc_pixel_set_confirm": "Are you sure you want to set pixel {0}? It will cost you {1}",
   "nc_hint": "Use `{0}nczoom x y` command to zoom in. Image is {1}x{2} pixels.",
+  "nc_insuff_payment": "Invalid payment.",
   "invalid_img_size": "Image must to be {0}x{1} pixels.",
   "no_attach_found": "No attachment found. Please send the image along with this command." 
 }