Improve how Talkback works with the timeline (#2404)

* Improve how Talkback works with the timeline

* Fix interaction test by adding test tag

* Disable reverse layout when a screen reader is enabled

This messes up with the ordering, but fixes the scrolling when a screen reader is used.

libraries/testtags/src/main/kotlin/io/element/android/libraries/testtags/TestTags.kt

@@ -74,4 +74,9 @@ object TestTags {
     val dialogPositive = TestTag("dialog-positive")
     val dialogNegative = TestTag("dialog-negative")
     val dialogNeutral = TestTag("dialog-neutral")
+
+    /**
+     * Timeline item.
+     */
+    val timelineItemSenderInfo = TestTag("timeline_item-sender_info")
 }