Send read receipts (#713)

* Send read receipts

* Add changelog

* Add tests.

* Optimise how sending read receipts work in the timeline.

* Move the check for send read receipts to the presenter

Also improve the way we find the first visible `Event` if we have `Virtual` ones in the timeline.

libraries/matrix/impl/src/main/kotlin/io/element/android/libraries/matrix/impl/timeline/RustMatrixTimeline.kt

@@ -107,4 +107,10 @@ class RustMatrixTimeline(
             Timber.v("Success back paginating for room ${matrixRoom.roomId}")
         }
     }
+
+    override suspend fun sendReadReceipt(eventId: EventId) = withContext(coroutineDispatchers.io) {
+        runCatching {
+            innerRoom.sendReadReceipt(eventId = eventId.value)
+        }
+    }
 }