fix(cli-example): optimize the example of the 'install' command line.

[sujoshua]

Since --helm-set is an alias of --set and only --set is listed in help, it would be confusing when example still use

# Install Cilium into Kubernetes context "kind-cluster1" and also set cluster
# name and ID to prepare for multi-cluster capabilities.
cilium install --context kind-cluster1 --helm-set cluster.id=1 --helm-set cluster.name=cluster1

Instead we should use set as follows

# Install Cilium into Kubernetes context "kind-cluster1" and also set cluster
# name and ID to prepare for multi-cluster capabilities.
cilium install --context kind-cluster1 --set cluster.id=1 --set cluster.name=cluster1

This way, users can easily find the correct flag in the --help command.

[maintainer-s-little-helper]

Commit d92407d does not contain "Signed-off-by".

Please follow instructions provided in https://docs.cilium.io/en/stable/contributing/development/contributing_guide/#developer-s-certificate-of-origin

[michi-covalent]

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