Fix crashes destroying conversation activity

app/src/main/java/org/thoughtcrime/securesms/conversation/v2/ConversationActivityV2.kt

@@ -852,9 +852,11 @@ class ConversationActivityV2 : PassphraseRequiredActionBarActivity(), InputBarDe
     }
 
     override fun onDestroy() {
+        if(::binding.isInitialized) {
             viewModel.saveDraft(binding.inputBar.text.trim())
             cancelVoiceMessage()
             tearDownRecipientObserver()
+        }
         super.onDestroy()
     }
     // endregion