Titulky: Could not find container element. No subtitles found.

[sambartik]

Describe the bug
The provider does not list any subtitles and logs the message Titulky.com: Could not find container element. No subtitles found.
The bug is caused because we are not checking for account premium status on each request, only during login. However a premium status can expire while still having a logged in session cached.

To Reproduce
Steps to reproduce the behavior:

1. Log in to provider with premium status
2. While the login session is cached, lose the premium status
3. Search for subtitles

Expected behavior
Provider should throw an exception saying that the account needs to be premium.

Software (please complete the following information):

• Bazarr: v1.4.6-beta.16

[sambartik]

You can assign me to this issue, morph. I'd get back to it when I can.