The observer should not expose 'out-of-scope' namespaces

Current situation

If I'm a user with a token granting access to namespaces a and b, when I get the channel list I will see all channels that I have access to, which is expected, but, for those environment, I can see all namespaces they are accessible from.

Desired outcome

I should not see 'out-of-scope' environments. I should only see, for those channels, the namespaces I have access to, or '*' if the environment is globally available.