fix(ShardingManager): do not spawn the last shard early
fix(ShardingManager): do not spawn the last shard early

An off-by-one error resulted in the last shard getting the delay of the second last one.
Closes #3181

appellation/discord.js,hydrabolt/discord.js,hydrabolt/discord.js,SpaceEEC/discord.js,appellation/discord.js,appellation/discord.js,SpaceEEC/discord.js,hydrabolt/discord.js,SpaceEEC/discord.js