update ai intro

The current chatbot intro message is:
Hello, I'm GeoDa.Ai chatbot! Let's do spatial analysis! Ask me anything about your data.

Let's change the last sentence to a suggestion for how to get the chatbot to know that the data was loaded. E.g. right now, if you load the data (stl_hom) and then ask: "I just loaded the stl_hom data. Can you summarize the data?" There's no response. Helping the user frame the question in a way so the bot realizes the data was loaded would be helpful.