Some urls behind pushbutton are not extracted from the AA dictionary

[calixteman]

Steps to reproduce the problem:

1. Open https://www.guidedesimpots.lu/wp-content/uploads/2019/02/160F-2019.pdf
2. The links behind FD, FO, DS, ... are not usable

These annotations correspond to a PushButton because their parent is and the action is in the AA dictionary associated to D (MouseDown).
So once #12429 is merged we can easily extract url from the action.
Since for security reasons we won't implement app.launchURL we must handle that stuff in same way as we do for A dict.

[timvandermeij]

This issue is possibly related to #9776.

[calixteman]

The issue in #9776 is slightly different since the actions in AA::D are /GoTo and here they're /JavaScript.
But finally thanks to your comment, I think I've a way better (and simpler) patch to handle the different cases.

[timvandermeij]

Fixed by the PR above.