Fix test_participantAddsReactionWhileUserIsOffline flakey test by awaiting message sent confirmation. (#6316)

Co-authored-by: André Mion <andremion@gmail.com>

Author: VelikovPetar

stream-chat-android-compose-sample/src/androidTestE2eDebug/kotlin/io/getstream/chat/android/compose/tests/ReactionsTests.kt

@@ -16,12 +16,14 @@
 
 package io.getstream.chat.android.compose.tests
 
+import io.getstream.chat.android.compose.pages.MessageListPage.MessageList.Message
 import io.getstream.chat.android.compose.robots.assertReaction
 import io.getstream.chat.android.compose.sample.ui.InitTestActivity
 import io.getstream.chat.android.compose.uiautomator.device
 import io.getstream.chat.android.compose.uiautomator.disableInternetConnection
 import io.getstream.chat.android.compose.uiautomator.enableInternetConnection
 import io.getstream.chat.android.compose.uiautomator.seconds
+import io.getstream.chat.android.compose.uiautomator.wait
 import io.getstream.chat.android.e2e.test.mockserver.ReactionType
 import io.qameta.allure.kotlin.Allure.step
 import io.qameta.allure.kotlin.AllureId
@@ -214,9 +216,8 @@ class ReactionsTests : StreamTestCase() {
             userRobot.login().openChannel()
         }
         step("AND user sends a message") {
-            userRobot
-                .sendMessage(sampleText)
-                .sleep(500) // to fix flakiness on CI
+            userRobot.sendMessage(sampleText)
+            Message.deliveryStatusIsSent.wait()
         }
         step("AND user becomes offline") {
             participantRobot.addReaction(type = ReactionType.LIKE, delay)