fixes Circles icon rendering in darkmode

[privatemaker]

Currently in the /settings/apps view when a user has dark theme enabled the Circles icon is black, when it should be white.

By adding attribute fill="#fff" to the SVG data this issue is resolved.

The only other place I could find the icon used is in the Contacts app and this change works there as well.

[github-actions]

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[privatemaker]

@ArtificialOwl maybe you want to push this simple fix through? The test suite failed on four phpunit tests which i'm 99.99% confident have nothing to do with my pull-request.