added check for multiple user objects with the same email address
added check for multiple user objects with the same email address

ssadedin/seqr,ssadedin/seqr,macarthur-lab/seqr,macarthur-lab/xbrowse,macarthur-lab/seqr,macarthur-lab/xbrowse,macarthur-lab/xbrowse,ssadedin/seqr,macarthur-lab/seqr,ssadedin/seqr,macarthur-lab/xbrowse,macarthur-lab/seqr,macarthur-lab/xbrowse,macarthur-lab/xbrowse,ssadedin/seqr,macarthur-lab/seqr