avoid UninitializedPropertyAccessException for optionsMenu

otherwise:

E  FATAL EXCEPTION: main
    Process: com.nextcloud.talk2, PID: 13169
    io.reactivex.exceptions.UndeliverableException: The exception could not be delivered to the consumer because it has already canceled/disposed the flow or the exception has nowhere to go to begin with. Further reading: https://github.com/ReactiveX/RxJava/wiki/What's-different-in-2.0#error-handling | kotlin.UninitializedPropertyAccessException: lateinit property optionsMenu has not been initialized
    	at io.reactivex.plugins.RxJavaPlugins.onError(RxJavaPlugins.java:367)
    	at io.reactivex.android.schedulers.HandlerScheduler$ScheduledRunnable.run(HandlerScheduler.java:126)
    	at android.os.Handler.handleCallback(Handler.java:942)
    	at android.os.Handler.dispatchMessage(Handler.java:99)
    	at android.os.Looper.loopOnce(Looper.java:226)
    	at android.os.Looper.loop(Looper.java:313)
    	at android.app.ActivityThread.main(ActivityThread.java:8757)
    	at java.lang.reflect.Method.invoke(Native Method)
    	at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:571)
    	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1067)
    Caused by: kotlin.UninitializedPropertyAccessException: lateinit property optionsMenu has not been initialized
    	at com.nextcloud.talk.conversation.info.ConversationInfoActivity.showOptionsMenu(ConversationInfoActivity.kt:214)
    	at com.nextcloud.talk.conversation.info.ConversationInfoActivity$fetchRoomInfo$1.onNext(ConversationInfoActivity.kt:670)
    	at com.nextcloud.talk.conversation.info.ConversationInfoActivity$fetchRoomInfo$1.onNext(ConversationInfoActivity.kt:652)
    	at io.reactivex.internal.operators.observable.ObservableObserveOn$ObserveOnObserver.drainNormal(ObservableObserveOn.java:201)
    	at io.reactivex.internal.operators.observable.ObservableObserveOn$ObserveOnObserver.run(ObservableObserveOn.java:255)
    	at io.reactivex.android.schedulers.HandlerScheduler$ScheduledRunnable.run(HandlerScheduler.java:124)
    	at android.os.Handler.handleCallback(Handler.java:942) 
    	at android.os.Handler.dispatchMessage(Handler.java:99) 
    	at android.os.Looper.loopOnce(Looper.java:226) 
    	at android.os.Looper.loop(Looper.java:313) 
    	at android.app.ActivityThread.main(ActivityThread.java:8757) 
    	at java.lang.reflect.Method.invoke(Native Method) 
    	at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:571) 
    	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1067) 

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

app/src/main/java/com/nextcloud/talk/conversation/info/ConversationInfoActivity.kt

@@ -211,9 +211,11 @@ class ConversationInfoActivity :
     }
 
     fun showOptionsMenu() {
-        optionsMenu.clear()
-        if (CapabilitiesUtilNew.isConversationAvatarEndpointAvailable(conversationUser)) {
-            menuInflater.inflate(R.menu.menu_conversation_info, optionsMenu)
+        if (::optionsMenu.isInitialized) {
+            optionsMenu.clear()
+            if (CapabilitiesUtilNew.isConversationAvatarEndpointAvailable(conversationUser)) {
+                menuInflater.inflate(R.menu.menu_conversation_info, optionsMenu)
+            }
         }
     }