Don't show series subscribe button for shows marked as "Completed"

Steps to reproduce

1. Open any TV Series/Anime that's marked as "Completed" i.e., no new episodes will be released for it.
2. Look for the "Subscribe for upcoming episodes" button on the top right(it looks like a bell) and press it.

Expected behavior

Button shouldn't exist on anime/TV Series that's marked as completed.

Actual behavior

Button works, and turns into its pressed state.

Cloudstream version and commit hash

4.5.4 e60453b

Android version

Android 15

Logcat

Other details

No response

Acknowledgements

• I am sure my issue is related to the app and NOT some extension.
• I have searched the existing issues and this is a new ticket, NOT a duplicate or related to another open issue.
• I have written a short but informative title.
• I have updated the app to pre-release version Latest.
• I will fill out all of the requested information in this form.

Reproduce the issue on an Android device using a completed TV series or anime, then locate the series detail screen and the logic controlling the "Subscribe for upcoming episodes" button. Done means the button is absent for completed shows while subscription controls still work for shows with upcoming episodes; add or run a relevant regression check if the project provides one.