Add new transitions report (matomo-org#13475)

* trying to add a report through visualization

* refs matomo-org#12865 added transitions report

* small tweak

* remove auto generated api

* apply review feedback

* add ui test, fix widget view

* fix ui test

* fix tests

* update screenshots

* fix various issues

* trying to fix tests

* fix tests

* Update expected screenshot tests.

* Try to fix random failure & update screenshots.

* add help text, add icon, do not fetch anything when no action name

* trying to fix tests

* tweak code

* run tests again

* Update expected screenshots.