Spoilered URLs sent from Telegram include `<span data-mx-spoiler>` in href on Matrix

[rom4nik]

Bridge @ 0068341. Issue as in title:

Event content on Matrix:

"content": {
    "body": "some text before the spoiler: https://matrix.org",
    "external_url": "https://t.me/c/4597680902/6021",
    "fi.mau.telegram.source": {
      "chat_id": 4597680902,
      "id": 6021,
      "peer_type": "chat",
      "space": 1714758850
    },
    "format": "org.matrix.custom.html",
    "formatted_body": "some text before the spoiler: <a href='http://<span data-mx-spoiler>https://matrix.org</span>'><span data-mx-spoiler>https://matrix.org</span></a>",
    "msgtype": "m.text"
  },

Depending on client, this URL might not be rendered at all (Element Desktop):

Or appear as a normal URL, but navigating to the incorrect URL taken from formatted_body (Element X Android):