Use `.orEmpty()` instead of `?: ""`

vector/src/main/java/im/vector/app/core/pushers/PushersManager.kt

@@ -41,7 +41,7 @@ class PushersManager @Inject constructor(
         currentSession.pushersService().testPush(
                 unifiedPushHelper.getPushGateway()!!,
                 stringProvider.getString(R.string.pusher_app_id),
-                unifiedPushHelper.getEndpointOrToken() ?: "",
+                unifiedPushHelper.getEndpointOrToken().orEmpty(),
                 TEST_EVENT_ID
         )
     }

vector/src/main/java/im/vector/app/core/pushers/UnifiedPushHelper.kt

@@ -191,7 +191,7 @@ class UnifiedPushHelper @Inject constructor(
         vectorPreferences?.setFdroidSyncBackgroundMode(mode)
         runBlocking {
             try {
-                pushersManager?.unregisterPusher(getEndpointOrToken() ?: "")
+                pushersManager?.unregisterPusher(getEndpointOrToken().orEmpty())
             } catch (e: Exception) {
                 Timber.d("Probably unregistering a non existant pusher")
             }

vector/src/main/java/im/vector/app/core/pushers/VectorMessagingReceiver.kt

@@ -192,7 +192,7 @@ class VectorMessagingReceiver : MessagingReceiver() {
         guardServiceStarter.start()
         runBlocking {
             try {
-                pushersManager.unregisterPusher(unifiedPushHelper.getEndpointOrToken() ?: "")
+                pushersManager.unregisterPusher(unifiedPushHelper.getEndpointOrToken().orEmpty())
             } catch (e: Exception) {
                 Timber.tag(loggerTag.value).d("Probably unregistering a non existant pusher")
             }