Use Shoelace Dialog for ConfirmDialog

[tvdeyen]

What is this pull request for?

We have our own Dialog JS class. We should not have a complicated component like this in our code base. Instead we should use the Shoelace Dialog that has better accessibility and UX.

Since our dialog is meant to load remote content we first migrate its little sister ConfirmDialog, which just displays text.

This also adds a remixicon theme to shoelace (based on the SVG sprite sheet) and updates Shoelace to 2.15.0 because of a bug in icon set registration.

Checklist

• [x] I have followed Pull Request guidelines
• [x] I have added a detailed description into each commit message

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 95.92%. Comparing base (f0b0403) to head (88454b5).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #2823 +/- ## ======================================= Coverage 95.92% 95.92% ======================================= Files 225 225 Lines 6128 6128 ======================================= Hits 5878 5878 Misses 250 250 ```

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.