Add polls to backups.

app/src/main/java/org/thoughtcrime/securesms/polls/PollOption.kt

@@ -10,7 +10,7 @@ import kotlinx.parcelize.Parcelize
 data class PollOption(
   val id: Long,
   val text: String,
-  val voterIds: List<Long>,
+  val voters: List<Voter>,
   val isSelected: Boolean = false,
   val isPending: Boolean = false
 ) : Parcelable

app/src/main/java/org/thoughtcrime/securesms/polls/Voter.kt

@@ -0,0 +1,18 @@
+/*
+ * Copyright 2025 Signal Messenger, LLC
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+package org.thoughtcrime.securesms.polls
+
+import android.os.Parcelable
+import kotlinx.parcelize.Parcelize
+
+/**
+ * Class to track someone who has voted in an option within a poll.
+ */
+@Parcelize
+data class Voter(
+  val id: Long,
+  val voteCount: Int
+) : Parcelable