Istio 1.5.+ update configmap istio-sidecard-injector via operator - please help

I have istio installed using istio operator and I’m looking for help on how to to update istio-sideca-injector.

I can do it manually but would like to how to automate this for future installation using istio installation via operator.

Manual edit:

kubectl edit configmap istio-sidecar-injector -n istio-system

Under:

containers:
  - name: istio-proxy

would like to add this in:

    lifecycle:
      preStop:
        exec:
          command: ["/bin/sh", "-c", "while [ $(netstat -plunt | grep tcp | grep -v envoy | wc -l | xargs) -ne 0 ]; do sleep 1; done"]

The context is to prevent proxy from shutting down before application finishing up its termination process including making connections out/in etc…

Please let me know if there is an option to update/patch configmap via operator / operator template etc…

Help is much appreciated.

Whiteseal.