Reaction summary view and sorting reactions by count and then timestamp (#942)

* Sort reactions by count and then timestamp

- Sort reactions within an aggregation by timestamp descending. This puts the most recent at the top, useful in cases like the reaction summary view or getting the most recent reaction.
- Sort aggregated reactions by count and then timestamp ascending, using the most recent reaction in the aggregation. This appends new aggregations on the end of the reaction layout.

* Add reaction summary view

* fix warnings

* Fix test unit tests and add sorting tests

- Fix broken build in test code
- Add a test for reaction sorting

* Remove default closure, move logic to presenter and add tests

* Update screenshots

* Fix imports

* Revert Screenshots I didn't update

* Fix imports remove screetshots

* Update screenshots

* Update screenshots

* Address comments.

* Update screenshots

* Remove unnecessary snapshotFlow

* Fix code quality checks

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Co-authored-by: ElementBot <benoitm+elementbot@element.io>

libraries/matrix/impl/src/main/kotlin/io/element/android/libraries/matrix/impl/timeline/item/event/EventTimelineItemMapper.kt

@@ -25,6 +25,7 @@ import io.element.android.libraries.matrix.api.timeline.item.event.EventReaction
 import io.element.android.libraries.matrix.api.timeline.item.event.EventTimelineItem
 import io.element.android.libraries.matrix.api.timeline.item.event.LocalEventSendState
 import io.element.android.libraries.matrix.api.timeline.item.event.ProfileTimelineDetails
+import io.element.android.libraries.matrix.api.timeline.item.event.ReactionSender
 import org.matrix.rustcomponents.sdk.Reaction
 import org.matrix.rustcomponents.sdk.EventItemOrigin as RustEventItemOrigin
 import org.matrix.rustcomponents.sdk.EventSendState as RustEventSendState
@@ -81,8 +82,12 @@ private fun List<Reaction>?.map(): List<EventReaction> {
     return this?.map {
         EventReaction(
             key = it.key,
-            count = it.count.toLong(),
-            senderIds = it.senders.map { sender -> UserId(sender.senderId) }
+            senders = it.senders.map { sender ->
+                ReactionSender(
+                    senderId = UserId(sender.senderId),
+                    timestamp = sender.timestamp.toLong()
+                )
+            }
         )
     } ?: emptyList()
 }