MM-12007 Add max dimensions to emoji images (#9379)

i18n/en.json

@@ -1008,6 +1008,10 @@
     "id": "api.emoji.upload.image.app_error",
     "translation": "Unable to create emoji. File must be a PNG, JPEG, or GIF."
   },
+  {
+    "id": "api.emoji.upload.large_image.too_large.app_error",
+    "translation": "Unable to create emoji. Image must be smaller than {{.MaxWidth}} by {{.MaxHeight}}."
+  },
   {
     "id": "api.emoji.upload.large_image.decode_error",
     "translation": "Unable to create emoji. An error occurred when trying to decode the image."