Fix CSP problems, file transition

[fernandops26]

The components that use transicion.js have problems with csp, this allows to avoid that problem, i replaced attr() by css(). Fix: #5630.

[cordoval]

bump @Banandrew \lgtm 👍 🚢 is good!

[tlewowski]

Uhm, any reason why is this waiting for several months already?

[amoerie]

Is there something that's holding back this PR? It's 6 months stale already.

[stale[bot]]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed in 30 days if no further activity occurs. Thank you for your contributions.

[amoerie]

It doesn't need activity, it needs a simple review. This fix is very minor but helps anyone who is serious about security.

[lasley]

Not sure why this is closed, but this is absolutely a good change

[Vringe]

Just hit the same issue, my dropdown icons cannot be displayed because CSP denies loading inline fonts. Any update on this?