Add test for additional form actions
Summary: This tests the newly added additional widget actions.
Test Plan:
Passes for me. Is my first GUI test, maybe the timing
needs to be slower for slower machines?
Reviewers: aacid
Reviewed By: aacid
Subscribers: okular-devel
Tags: Okular
Maniphest Tasks: T8627
Differential Revision: https://phabricator.kde.org/D13170