Stop removing emoji joiner character from nicknames

Many emojis are using zero width joiner character to actually concatenate two different emojis into a single one. I know Discord doesn't support new emojis (“next week,” huh?), but there is NO point besides protection from empty nicknames to remove U+200D character, so to break native support for emojis on new systems: for the empty nicknames, smarter expressions must be used.

Example:

• "\ud83d\udc68\u200d\ud83c\udfa4" results "👨‍🎤", but removing "\u200d" will result "👨🎤"
• "\ud83c\udff3\u200d\ud83c\udf08" results "🏳‍🌈", but removing "\u200d" will result "🏳🌈"