ActivitiesActivityIT: add waitForIdleSync() after sleeps

Signed-off-by: Álvaro Brey Vilas <alvaro.brey@nextcloud.com>

src/androidTest/java/com/nextcloud/client/ActivitiesActivityIT.kt

@@ -66,6 +66,7 @@ class ActivitiesActivityIT : AbstractIT() {
         }
 
         shortSleep()
+        waitForIdleSync()
 
         Screenshot.snapActivity(sut).record()
     }
@@ -82,6 +83,7 @@ class ActivitiesActivityIT : AbstractIT() {
         }
 
         shortSleep()
+        waitForIdleSync()
 
         screenshot(sut)
     }
@@ -173,6 +175,7 @@ class ActivitiesActivityIT : AbstractIT() {
         }
 
         shortSleep()
+        waitForIdleSync()
 
         screenshot(sut)
     }
@@ -189,6 +192,7 @@ class ActivitiesActivityIT : AbstractIT() {
         }
 
         shortSleep()
+        waitForIdleSync()
 
         screenshot(sut)
     }