UI test for exporting all public keys

[tomholub]

reopening for:

Good for this particular PR, but it would be good to test this with UI tests (click the export all button, and expect pubkeys to come out).

Originally posted by @tomholub in #3659 (comment)

[sosnovsky]

Hi @ioanatflowcrypt, please check if we have such test or it needs to be implemented, thanks!