[ie/dplay] Fix extractors

[bashonly]

Closes #1623, #2138, #2361, #3841, #8026, #10421

TODO:

• add tests
• cleanup duplicate/unnecessary _update_disco_api_headers() methods
• set _DISCO_CLIENT_VER in subclasses as necessary

Template

Before submitting a pull request make sure you have:

• At least skimmed through contributing guidelines including yt-dlp coding conventions
• Searched the bugtracker for similar pull requests

In order to be accepted and merged into yt-dlp each piece of code must be in public domain or released under Unlicense. Check all of the following options that apply:

• I am the original author of this code and I am willing to release it under Unlicense

What is the purpose of your pull request?

• Fix or improvement to an extractor (Make sure to add/update tests)