Fix for org/teams API permissions

[kamicut]

What I am changing

• Fix the API permissions for the org/:id/teams call

How I did it

• We add the can('organization:view-members') permission to this API call: if an org is public, you can view its teams and members, otherwise you have to be a member of the org

How you can test it

• Try calling the API for a private org with a non-org member

Related Issues

• closes API Permissions #274

[vgeorge]

@kamicut I confirm I wasn't able to see members of a private team, this looks good to merge.