PollHistory : simplify so we only have one Node. Also enrich PollHistoryState.

libraries/matrix/api/src/main/kotlin/io/element/android/libraries/matrix/api/room/MatrixRoom.kt

@@ -240,7 +240,7 @@ interface MatrixRoom : Closeable {
      */
     fun getWidgetDriver(widgetSettings: MatrixWidgetSettings): Result<MatrixWidgetDriver>
 
-    suspend fun pollHistory(): MatrixTimeline
+    fun pollHistory(): MatrixTimeline
 
     override fun close() = destroy()
 }

libraries/matrix/api/src/main/kotlin/io/element/android/libraries/matrix/api/timeline/MatrixTimeline.kt

@@ -23,9 +23,9 @@ import kotlinx.coroutines.flow.StateFlow
 interface MatrixTimeline : AutoCloseable {
 
     data class PaginationState(
-        val isBackPaginating: Boolean,
-        val hasMoreToLoadBackwards: Boolean,
-        val beginningOfRoomReached: Boolean,
+        val isBackPaginating: Boolean = false,
+        val hasMoreToLoadBackwards: Boolean = true,
+        val beginningOfRoomReached: Boolean = false,
     ) {
         val canBackPaginate = !isBackPaginating && hasMoreToLoadBackwards
     }