Core: don't replace the indices within the ActionRequest with the concrete ones, and make sure check blocks is executed on concrete indices

Concrete indices is now called multiple times when needed instead of changing what's inside the incoming request with the concrete indices. Ideally we want to keep the original aliases or indices or wildcard expressions in the request.

Also made sure that the check blocks is done against the concrete indices, which wasn't the case for delete index, delete mapping, open index, close index, types exists and indices exists.

Closes #6694
Closes #6777