catch openai rate limit error (#7658)

api/controllers/web/error.py

@@ -125,3 +125,11 @@ class WebSSOAuthRequiredError(BaseHTTPException):
     error_code = "web_sso_auth_required"
     description = "Web SSO authentication required."
     code = 401
+
+
+class InvokeRateLimitError(BaseHTTPException):
+    """Raised when the Invoke returns rate limit error."""
+
+    error_code = "rate_limit_error"
+    description = "Rate Limit Error"
+    code = 429