Add support for `hostUsers` to keda helm charts

I would like a flag in the keda helm charts enabling me to set `hostUsers: false`.

### Use-Case

With Kubernetes 1.36 `hostUsers` is a graduated user namespace pod isolation feature. Folks wishing to take advantage of this need a clear place to toggle this feature

### Specification

- [ ] Helm flag to toggle the boolean flag `hostUsers`

