JERUSALEM (Reuters) -Sanctioned Russian oligarch Roman Abramovich was seen in Tel Aviv’s Ben Gurion airport on Monday shortly before a jet linked to him took off for Istanbul. A photograph obtained by Reuters showed Abramovich, owner of Britain’s Chelsea soccer club, sitting in the airport’s VIP lounge with a face mask pulled down over his chin. Reuters could not verify independently that he actually boarded the flight. Abramovich, who also holds Israeli and Portuguese citizenship, was among seven Russian billionaires added to the British sanctions list on Thursday as part of efforts to isolat…