Doesn't sound ironic at all to me, tbh. IMO, it's either another example of his clumsiness (which is likely) or he just doesn't want to be bothered with reading something. The three-time Wimbledon champion wants to be informed instead. Actually Julia can count herself lucky that he graced her with his attention in the first place.
And conversation? What did he expect her to answer him? "Well Boris, in my letter I write about my season, team, great sponsors, etc..." I mean if he wanted to get a little conversation started he just could have said: "good letter" (even if he didn't mean it), then he would have given Julia an easy opportunity to answer.
We'll see how she reacts