[KRun] Don’t follow redirection to speed up and avoid incorrect behavior

Summary: BUG: 354246

Test Plan:
Launch kde-open5 <URL to a website you have an account and that redirects when not connected>, e.g. <https://twitter.com/i/notifications>.
If it works, we see the correct URL, and not <https://twitter.com/login?redirect_after_login=%2Fi%2Fnotifications>.

Reviewers: #frameworks, dfaure, cfeck

Reviewed By: dfaure

Subscribers: plasma-devel, anthonyfieroni, ngraham, kde-frameworks-devel

Tags: #frameworks, #plasma

Differential Revision: https://phabricator.kde.org/D15189