feat: Update manifests to match upstream kfp 2.16.0 release

[mvlassis]

Ref: canonical/kfp-operators#869

This PR updates the charms according to the update to the manifests files corresponding to the 2.16.0 release of Kubeflow pipelines. This task is part of the team's upgrade to Kubeflow 26.03.

The diff between the 2 version was generated by following the instructions on the upstream README. It can be found here.

[MattiaSarti]

suggestion (blocking): while I understand the necessity of changing user ID and group ID with the upstream image, I would not go for root and I would try some other ID, instead, if it was possible to avoid the temporary changes to run it as root even on latest/edge. For example, have we tried with 1000, like they do upstream? They have securityContext.runAsNonRoot set to true, so I don't expect root privileges to be necessary.

[mvlassis]

It seems that running as user 1000 creates a permission error on the Pebble side: https://github.com/canonical/envoy-operator/actions/runs/24070484106/job/70206016603?pr=203

[MattiaSarti]

juju.errors.JujuError: {"error":"cannot upload charm: invalid charm archive: parsing containers: container "envoy" has invalid uid 1000: uid cannot be in reserved range 1000-9999","error-code":"bad request"}

@mvlassis, then feel free to use root, it's an intrinsic limitation of Juju, as confirmed from the error's logs:

juju.errors.JujuError: {"error":"cannot upload charm: invalid charm archive: parsing containers: container "envoy" has invalid uid 1000: uid cannot be in reserved range 1000-9999","error-code":"bad request"}