Add spacing for Genmoji Tapbacks in HTML exports

[ReagentX]

Genmoji sent as Tapbacks are missing a newline or a space between the sticker effect and the Genmoji prompt:

Interestingly, you can add a sticker effect to a normal sticker, but you can't add one to a Genmoji; perhaps for Genmoji we should omit the sticker effect text altogether.

This field will be populated with the prompt used to generate the Genmoji:

imessage-exporter/imessage-database/src/tables/attachment.rs

Lines 78 to 79 in cd8acd5

	/// The prompt used to generate a Genmoji
	pub emoji_description: Option<String>,

We can determine if an Attachment is a Genmoji by checking the sticker_user_info blob if the aforementioned field is populated:

[ReagentX]

Also worth noting that standalone stickers get the correct newlines: