Fix poll percentage bug

Summary

Sometimes polls in Soapbox display batshit numbers that make no sense. This is because it divides by voters_count and not votes_count.

When you visit the polls endpoint, it sometimes returns a lower number of voters than votes. Example: https://iddqd.social/api/v1/polls/50338112

{
  "emojis": [],
  "expired": true,
  "expires_at": "2024-01-11T04:23:07.000Z",
  "id": "50338112",
  "multiple": false,
  "options": [
    {
      "title": "Yes",
      "votes_count": 10
    },
    {
      "title": "No",
      "votes_count": 3
    }
  ],
  "pleroma": {
    "non_anonymous": false
  },
  "voters_count": 7,
  "votes_count": 13
}

See results below.

Screenshots (if appropriate):

10/7 = 1.43, hence this (incorrect):

10/13=0.77, hence this (correct):