Fix / crash not called on UI Thread

vector/src/main/java/im/vector/riotx/features/popup/PopupAlertManager.kt

@@ -45,8 +45,10 @@ object PopupAlertManager {
         synchronized(alertFiFo) {
             alertFiFo.add(alert)
         }
+        weakCurrentActivity?.get()?.runOnUiThread {
             displayNextIfPossible()
         }
+    }
 
     fun cancelAlert(uid: String) {
         synchronized(alertFiFo) {
@@ -62,10 +64,12 @@ object PopupAlertManager {
 
         //it could also be the current one
         if (currentAlerter?.uid == uid) {
+            weakCurrentActivity?.get()?.runOnUiThread {
                 Alerter.hide()
                 currentIsDismissed()
             }
         }
+    }
 
 
     fun onNewActivityDisplayed(activity: Activity) {