Model says it's thinking, but it's really downloading the model

Testing #335588

Maybe don't show Considering/Thinking/etc. when the model is downloading? In the sense that it's a different kind of loader where the agent itself isn't thinking. Or maybe it's just a bit jarring to have three different spinners at the same time ("Considering", the chatbox shiny border, and the toast progress bar); maybe the model download progress bar could be shown in the chat itself?