feat(helm): add loadBalancerIP to service spec

[pdemagny]

What changes are being made and why?

Hi !

I'd like to add loadBalancerIP to service spec to allow use cases such as Internal Load Balancers on Google Kubernetes Engine with static internal IP reserved in advance.
It helps with:

• Increasing security by not exposing the service with an external IP.
• Allowing more advanced automation in provisioning infrastructure.

See this, this and this.

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How the changes have been QAed?

Tested on GKE v1.27.8-gke.1067004 STABLE Release Channel with the Kestra chart deployed with helmfime 0.162.0 as a local chart and these values:

service:
  type: LoadBalancer
  loadBalancerIP: 10.42.0.30
  annotations:
    networking.gke.io/load-balancer-type: "Internal"

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[loicmathieu]

LGTM, thanks