Dont validate namespace in CI

[fordneild]

Description

A few sentences describing the overall goals of the pull request's commits.

Currently there exists a deadlock in the following situation:

• you are rendering the helm chart without a release name (as is common in CI tests)
• you are using managerRbac.namespaces

First, lets acknowledge that if isCI is set, we assume we dont have a release name/namespace. Therefore the chart skips the validation that release name is traffic-manager, which makes sense. The chart then defaults the traffic manager namespace to be ambassador. However this will throw if ambassador is not included in the list of namespaces.

Checklist

• I made sure to update ./CHANGELOG.yml.
• I made sure to add any docs changes required for my change (including release notes).
• My change is adequately tested.
• I updated CONTRIBUTING.md with any special dev tricks I had to use to work on this code efficiently.
• Once my PR is ready to have integration tests ran, I posted the PR in #telepresence-dev in the datawire-oss slack so that the "ok to test" label can be applied.

[thallgren]

@fordneild , can you give a bit more context to this? Our CI tests will indeed provide a chart release-name when running, and for an external CI where Telepresence is involved, I'd imaging that you'd use the Helm chart that is published here.