Subscribe Button Available Without Login

Expected behavior

As the application doesn't have an feature to login into an account, the subscribe button should not be available.

Actual behavior

Even though there is no login feature available the user is able to subscribe the channel which should not be possible.

How to reproduce

1. Download the NewPipe appliaction.
2. Click on any video and click on the Channel name.
3. Click the subscribe button beside the channel name.

** Browser:** not available

** Operating system:** Andriod 4.4.4 to Android 7.0

Recording Of The Bug

https://youtu.be/2v_mz3LDcPc