[cookies] Fix --cookies-from-browser for snap Firefox

[Grub4K]

IMPORTANT: PRs without the template will be CLOSED

Description of your pull request and other information

Implement support for --cookies-from-browser for snap Firefox and do more specific searching for theProfiles dirs. It also allows os.altsep as a path separator for _is_path, so that / is correctly categorized on Windows.

This PR has the side effect of including glob, as well as no longer searching infinitely deep, therefore speeding up the cookie extraction by an immense amount.

Fixes #7520, Closes #9011

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[mmafic]

Is it possible to add support for custom profile directories? Firefox allows you to choose a location when creating a profile, the list of all profiles is stored in profile.ini, which is in AppData/Roaming on Windows.

[bashonly]

Is it possible to add support for custom profile directories?

you can already pass any profile directory path, e.g.
--cookies-from-browser "firefox:/path/to/profile"

[Grub4K]

...the list of all profiles is stored in profile.ini, which is in AppData/Roaming on Windows.

This is not a bad idea. I will create a POC that does this to see if it makes sense to implement.