Milestone emails for the big firsts, and a shorter friends email

A milestone email now comes only for a big first: a new arena, a new league in Path of Legends, a new best trophy band, an Evolution or Hero form unlocked, or a career milestone (every 1,000 career wins, and each Collection Level step). Cards unlocked and badge levels no longer send one each; Tuesday's Arena email counts them for each of your players ("3 cards unlocked, 2 badge levels") with a link to your timeline, where every one is still listed newest first. Your friends this week draws each clan as a headline and at most three of the week's facts, with the rest counted and a link to the clan, names everyone quiet for 30 days or more in one line, counts a friend's unlocks and badges instead of listing them, and no longer ends a sentence with two full stops. MCP 11.5.2 and JSON API 3.1.0 unchanged.