Prevent crash when conversation fragment resumes if viewmodel doesn't have a chatRoom stored

app/src/main/java/org/linphone/ui/main/chat/fragment/ConversationFragment.kt

@@ -910,6 +910,12 @@ open class ConversationFragment : SlidingPaneChildFragment() {
     override fun onResume() {
         super.onResume()
 
+        if (!viewModel.isChatRoomInitialized()) {
+            Log.w("$TAG Fragment resuming but no chatRoom in viewModel, going back")
+            goBack()
+            return
+        }
+
         viewModel.updateCurrentlyDisplayedConversation()
 
         // Wait for items to be displayed