Import upstream patch in www/nextcloudclient port

[madpilot]

Summary

As mentioned in bug 241823 [1] nextcloudclient 2.6.1 has a regression, it forces the keyring to be rewwritten every time it polls the server.

I filed a bug report upstream [2] for this and a fix has been provided [3]. I'd like to import it in our port with this patch.

[1] https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=241823
[2] https://github.com/nextcloud/desktop/issues/1592
[3] https://github.com/nextcloud/desktop/commit/dcc84d35085d790a53b472d1edba663832af238a

Test Plan

Already tested in poudriere on supported versions and running it on my machines (desktop and laptop)

[madpilot]

Committed in r518779