ZURICH (Reuters) - The surveillance scandal at Credit Suisse cost former Chief Executive Tidjane Thiam part of his bonus in 2019, when his overall compensation fell 15% to 10.7 million Swiss francs (9.23 million pounds), the Swiss bank's annual report showed on Wednesday.Thiam "has led by example in terms of personal commitment to the group's conduct and ethics standards, but recognising that the observation matter had a significant impact on the group, his non-financial assessment score has..