Add missing emit_exchange_error_event method

Added emit_exchange_error_event method to WebChatBridge to comply with UiPathChatProtocol.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

Author: AAgnihotry

src/uipath/dev/services/chat_bridge.py

@@ -54,6 +54,10 @@ async def emit_exchange_end_event(self) -> None:
         if self.on_exchange_end:
             self.on_exchange_end()
 
+    async def emit_exchange_error_event(self, error: Exception) -> None:
+        """Send an exchange error event."""
+        logger.error(f"Exchange error: {error}")
+
     async def wait_for_resume(self) -> dict[str, Any]:
         """Wait for the user to respond to an interrupt."""
         self._resume_event.clear()