I tried to enter a test system prompt in the preferences, but when I try to delete it to leave it blank again, I get an error – I have to leave at least one character. Furthermore, I found it more useful to have it within the chats because I used it in a single chat that I needed for translations and I instructed it to be a translator. If I write this in the first message of the chat, is it equivalent to the result I used to get by writing the instructions in the system prompt?