graphql: Add setRepoPermissionsUnrestricted
Created by: ryanslade
Add the setRepoPermissionsUnrestricted
mutation to out explicit permissions API.
This allows an admin to set the unrestricted
column in our repo_permissions
table
which makes a repo visible to all users on the instance.
Part of https://github.com/sourcegraph/sourcegraph/issues/34631
Test plan
Unit and integration tests added