fix(argo-rollouts): Change type of trafficRouterPlugins and trafficRouterPlugins as list

[taer]

The change I made here https://github.com/argoproj/argo-helm/pull/3014 broken the examples.

This works w/ my original change:

controller:
  trafficRouterPlugins:
    - name: "argoproj-labs/gatewayAPI"
      location: "https://github.com/argoproj-labs/rollouts-plugin-trafficrouter-gatewayapi/releases/download/v0.4.0/gatewayapi-plugin-linux-arm64"
      sha256: "07e2fe515c900899c96777aac0ab490437a3d62c8adb94512ccb8b859325eb11"

But the example shows stringification is needed.

I feel having it "look like a real thing instead of a string" is more user friendly.

Checklist:

• [X] I have bumped the chart version according to versioning
• [X] I have updated the documentation according to documentation
• [X] I have updated the chart changelog with all the changes that come with this pull request according to changelog.
• [X] Any new values are backwards compatible and/or have sensible default.
• [X] I have signed off all my commits as required by DCO.
• [X] My build is green (troubleshooting builds).

[taer]

My prior change was basically a breaking one.

I assumed that no one was using the values.yaml for plugins since it wasn't rendering according to the docs.

But that ship sailed, and oops.

I will renumber this build to be a non-patch change... It's just docs, but follows up to the actual breaking change for anyone who worked around the initial issue.

[taer]

If y'all are ok w/ this, we should delete 2.37.8 since it was in fact a breaking change.. Thanks @michel-gleeson