[Enhancement] `switch namespace <namespace>` should set the namespace without refresh if it exists in cache.

[sherifabdlnaby]

Currently switch namespace <namespace> command will always attempt to fetch the fresh list of namespaces from the cluster even if the namespace already exists in the cache. This is unintuitive, especially that this is not the behavior of the interactive version switch namespace command.

Implementing this along side #86 will help with switch namespaces rapidly (and using terminal history and history auto-completion) to switch back and forth!

[danielfoehrKn]

Sorry for the delay. I agree, that's a good feature request. Not sure when I'll be able to tackle this, so if someone is willing to jump in, I would appreciate it.