Namespace-prefixed sequences aren't supported #168

When users define sequences that include the namespace, e.g.

        sequences:
          my-sequence:
            actions: >-
              namespace/auth,
              namespace/real-action

They get an error:

 ›   Sequence component 'namespace/real-action' does not exist (sequence =
 ›    'my-sequence')

This is because in the plugin, we track the action in the sequence as namespace/auth for example

But the list of actions we get from the config library tracks actions only in name, e.g. auth

Namespace-prefixed actions in a sequence are a valid Runtime use case that we should look into supporting