Revert "Changed Friends table to have 165-sized varchars on PrincipalID and FriendID. The reason for this number is the following: there is a combined key of these 2 fields; apparently MySql can't handle keys larger than 1000 bytes; when the table is created with utf8 encoding, this combined key is bigger than 1000 bytes, and the migration fails. WARNING: this is not a new migration! People who have gone through this migration and failed should update the sizes of these fields manually."
This reverts commit 3fa54a156a.