Add external link in pages details modal

[Maskoe]

Changes

I noticed the details pages modal does not let me navigate to the external link like the dashboard top pages section lets me do. So I added it to the modal too.

The code is mostly taken from "assets/js/dashboard/stats/reports/list.js" and minimally adjusted. This guy noticed it too. https://feedback.plausible.io/267

Tests

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Changelog

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Documentation

• [X] This change does not need a documentation update

Dark mode

• [X] The UI has been tested both in dark and light mode

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