frontend: don't insert+commit in create_after event
    
    Seems like create_all() is sensitive to ordering.  So instead of calling
    session.commit() directly in the listens_for() hook, delegate the
    commit() to the create_all() caller.
    
    This fix is needed on F35 with SQLAlchemy 1.4.29.
    
    Reported: https://lists.fedoraproject.org/archives/list/copr-devel@lists.fedorahosted.org/thread/ENTFM7IPMVOEE3XBCOELPBFF56RLLHDV/
    Merges: #2027