[MM-29240] Improve buffer handling of UploadEmojiImage (#25536)

server/i18n/en.json

@@ -1852,6 +1852,10 @@
     "id": "api.emoji.upload.open.app_error",
     "translation": "Unable to create the emoji. An error occurred when trying to open the attached image."
   },
+  {
+    "id": "api.emoji.upload.seek.app_error",
+    "translation": "Unable to seek to file start."
+  },
   {
     "id": "api.error_get_first_admin_complete_setup",
     "translation": "Error trying to retrieve first admin complete setup from the store."