fix to keep entered text when app is in background

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

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

@@ -542,7 +542,9 @@ class ChatActivity :
 
         initVoiceRecordButton()
 
-        binding?.messageInputView?.inputEditText?.setText(sharedText)
+        if (sharedText.isNotEmpty()) {
+            binding?.messageInputView?.inputEditText?.setText(sharedText)
+        }
         binding?.messageInputView?.setAttachmentsListener {
             AttachmentDialog(this, this).show()
         }