fix(mfm): remove duplicate br tag/newline (#8616)

packages/backend/src/mfm/from-html.ts

@@ -6,6 +6,9 @@ const urlRegex     = /^https?:\/\/[\w\/:%#@$&?!()\[\]~.,=+\-]+/;
 const urlRegexFull = /^https?:\/\/[\w\/:%#@$&?!()\[\]~.,=+\-]+$/;
 
 export function fromHtml(html: string, hashtagNames?: string[]): string {
+	// some AP servers like Pixelfed use br tags as well as newlines
+	html = html.replace(/<br\s?\/?>\r?\n/gi, '\n');
+
 	const dom = parse5.parseFragment(html);
 
 	let text = '';