[ie/tiktok] Extract via mobile API only if app_info is passed

[bashonly]

Since our hardcoded IIDs have been blocked and since mobile API extraction is presumably now hopeless, the extractor shouldn't even bother with the mobile API by default. Instead, it will only attempt API extraction if the app_info extractor-arg has been passed (i.e. the user has provided their own IID).

Partially addresses #9506

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
• Checked the code with flake8 and ran relevant tests

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)