Ads files redirected

[max-ostapenko]

Sometimes sellers.json redirects to the main adtech domain (for some business groups or managed domains), and the original page would be listed as a seller/publisher page on the file. Need to use the domain from redirect URL, instead of page.

• tracking redirect final url

Plus several updates to the test action:

• forcing WPT requests to use POST method to send all the custom metrics code (fixes 'Too long URL' error),
• in some cases the length of a PR comment content is too long (65K chars limit), so saving .md file as artifact instead,
• moved most of the code out of yaml to simplify the workflow update process

As the changes are not yet applied in test check - it fails. See https://github.com/max-ostapenko/custom-metrics/pull/1 instead.

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Test websites:

• https://www.example.com/

[max-ostapenko]

@tunetheweb just want to clarify that regardless of failing checks, it's ready for review and hopefully merge.