fix: show loading indicator during tool execution (CopilotKit#3055)

The loading spinner only appeared when the last message had role "user".
During tool execution the last message can have role "tool", hiding the
indicator. Now also show it when the trailing message is a tool result.

Author: jpr5

packages/react-ui/src/components/chat/Messages.tsx

@@ -112,9 +112,9 @@ export const Messages = ({
             />
           );
         })}
-        {messages[messages.length - 1]?.role === "user" && inProgress && (
-          <LoadingIcon />
-        )}
+        {inProgress &&
+          (messages[messages.length - 1]?.role === "user" ||
+            messages[messages.length - 1]?.role === "tool") && <LoadingIcon />}
         {interrupt}
         {chatError && ErrorMessage && (
           <ErrorMessage error={chatError} isCurrentMessage />