[KdePlasma-Addons/POTD/NOAA] Fixed RegEx string of landing page
Summary: 'Image of the day' has a new landing page everyday. This patch fixes the RegEx string that fetches the web address of the landing page.
Test Plan: All plugins should work as usual.
Reviewers: davidedmundson, ngraham
Reviewed By: davidedmundson, ngraham
Subscribers: ngraham, plasma-devel
Differential Revision: https://phabricator.kde.org/D18232