Fix updating unread marker if not to latest chunk

SetReadMarkerTask was not updating the read marker when both the old and
the new fully read eventId weren't in the last chunk, even when the new
one was after the first one.

changelog.d/5481.bugfix

@@ -0,0 +1 @@
+Fix sometimes read marker not properly updating

matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/database/query/ReadQueries.kt

@@ -94,7 +94,7 @@ internal fun isReadMarkerMoreRecent(realmConfiguration: RealmConfiguration,
             val eventToCheckIndex = eventToCheck?.displayIndex ?: Int.MAX_VALUE
             eventToCheckIndex <= readMarkerIndex
         } else {
-            eventToCheckChunk?.isLastForward == false
+            eventToCheckChunk?.isLastForward == false && readMarkerChunk?.isLastForward == true
         }
     }
 }