[extractor/weverse] Fix username check for invalid accounts

[seproDev]

IMPORTANT: PRs without the template will be CLOSED

Description of your pull request and other information

The username check currently fails if the username is invalid due to the API now returning a status code of 400 or 404 instead of 200 for invalid and unregistered accounts respectively.

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

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• I am the original author of this code and I am willing to release it under Unlicense
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What is the purpose of your pull request?

• Fix or improvement to an extractor (Make sure to add/update tests)
• New extractor (Piracy websites will not be accepted)
• Core bug fix/improvement
• New feature (It is strongly recommended to open an issue first)

Copilot Summary

🤖 Generated by Copilot at c9cb638

Summary

🛠️📥🚦

Fix login issue for some users in weverse.py by handling different API status codes. Add expected_status parameter to _download_json function.

_perform_login changed
API status codes vary
Autumn of errors

Walkthrough

• Allow different HTTP status codes for username check in _perform_login (link)
• Add expected_status parameter to _download_json call in _perform_login (link)
• Fix login issue for some users with valid usernames (link)