Emojis, stickers and sounds

A separate load part ("Emojis, stickers & sounds").

• Replace: the server's emojis, stickers and sounds are made to match the backup - those not in it are deleted. On the same server, ones that still exist are kept and only updated (saves uploads).
• Repair: only missing ones are created; nothing is deleted or renamed.
• Emojis get their role restrictions back. Forum tags, default reactions and sounds get their custom emojis back.
• Slots depend on the boost level (emojis 50–250 each for static/animated, stickers 5–60, sounds 8–48). What doesn't fit is listed in the result.
• Lottie stickers (animated, e.g. Discord's own) can only be uploaded by verified and partnered servers.
• Emojis of integrations (e.g. Twitch) aren't backed up - the integration brings them back.
• Discord limits emoji uploads; many emojis make this step take a while.