opentelemetry metrics field not working

### Is there an existing issue for this? - [x] I have searched the existing issues ### Kong version (`$ kong version`) 3.9.1 ### Current Behavior When following this documentation: https://developer.konghq.com/plugins/opentelemetry/examples/enable-otel/ with: ``` _format_version: "3.0" plugins: - name: opentelemetry config: sampling_rate: 1.0 metrics: endpoint: http://otel-collector.monitoring-system:4318/v1/metrics push_interval: 10 traces_endpoint: http://otel-collector.monitoring-system:4318/v1/traces ``` I get this error: ``` 2026/04/20 02:46:00 [error] 84#0: init_by_lua error: /usr/local/share/lua/5.1/kong/init.lua:731: error parsing declarative config file /tmp/kong.yaml: in 'plugins': - in entry 2 of 'plugins': in 'config': in 'metrics': unknown field stack traceback: [C]: in function 'error' /usr/local/share/lua/5.1/kong/init.lua:731: in function 'init' init_by_lua(nginx-kong.conf:46):3: in main chunk nginx: [error] init_by_lua error: /usr/local/share/lua/5.1/kong/init.lua:731: error parsing declarative config file /tmp/kong.yaml: in 'plugins': - in entry 2 of 'plugins': in 'config': in 'metrics': unknown field stack traceback: [C]: in function 'error' /usr/local/share/lua/5.1/kong/init.lua:731: in function 'init' init_by_lua(nginx-kong.conf:46):3: in main chunk Error: /usr/local/share/lua/5.1/kong/cmd/start.lua:99: failed to start nginx (exit code: 1) ``` ### Expected Behavior Removing the "metrics" field works fine: traces are sent to otel. But I need/want metrics. ### Steps To Reproduce _No response_ ### Anything else? _No response_