avoid UninitializedPropertyAccessException for spreedCapabilities

reported issue on gplay console was:

Exception kotlin.UninitializedPropertyAccessException: lateinit property spreedCapabilities has not been initialized
  at com.nextcloud.talk.chat.ChatActivity.getSpreedCapabilities (ChatActivity.kt:284)
  at com.nextcloud.talk.chat.ChatActivity.processExpiredMessages (ChatActivity.kt:2536)
  at com.nextcloud.talk.chat.ChatActivity.access$processExpiredMessages (ChatActivity.kt:204)
  at com.nextcloud.talk.chat.ChatActivity$initObservers$10$1.invokeSuspend (ChatActivity.kt:820)

This is just a hotfix while hoping processExpiredMessages is executed again while spreedCapabilities are available.

To improve the situation in the long term, we should move more logic to viewModel and have better control over sequence of actions.

Signed-off-by: Marcel Hibbe <dev@mhibbe.de>

app/src/main/java/com/nextcloud/talk/chat/ChatActivity.kt

@@ -2535,8 +2535,12 @@ class ChatActivity :
             }
         }
 
-        if (CapabilitiesUtil.hasSpreedFeatureCapability(spreedCapabilities, SpreedFeatures.MESSAGE_EXPIRATION)) {
-            deleteExpiredMessages()
+        if (this::spreedCapabilities.isInitialized) {
+            if (CapabilitiesUtil.hasSpreedFeatureCapability(spreedCapabilities, SpreedFeatures.MESSAGE_EXPIRATION)) {
+                deleteExpiredMessages()
+            }
+        } else {
+            Log.w(TAG, "spreedCapabilities are not initialized in processExpiredMessages()")
         }
     }