CLI - Tell users if they're already logged in (#1955)

Co-authored-by: Zeke Foppa <[email protected]>

crates/cli/src/subcommands/login.rs

@@ -96,6 +96,8 @@ async fn spacetimedb_token_cached(config: &mut Config, host: &Url, direct_login:
     // Currently, this token does not expire. However, it will at some point in the future. When that happens,
     // this code will need to happen before any request to a spacetimedb server, rather than at the end of the login flow here.
     if let Some(token) = config.spacetimedb_token() {
+        println!("You are already logged in.");
+        println!("If you want to log out, use spacetime logout.");
         Ok(token.clone())
     } else {
         let token = if direct_login {