common-ostree: Remove redundant entry for toolbox
    
    Toolbx was added to the default Fedora Workstation installation for
    Fedora 37 [1].  Therefore, it already gets pulled in through
    fedora-common-ostree-pkgs.yaml.
    
    [1] fedora-comps commit cdbc1f4ee0f28684
        https://pagure.io/fedora-comps/c/cdbc1f4ee0f28684
        https://pagure.io/fedora-workstation/issue/320
    
    https://pagure.io/workstation-ostree-config/pull-request/420