Fixing bugs in new folders in tabs feature

Summary:
Fixing bug where urls in secondary view containers would not be considered
for the open new folders in tabs feature.

Test Plan: Manual testing. Testing for no regressions. Testing that URL is found if in secondary view container

Reviewers: elvisangelaccio

Reviewed By: elvisangelaccio

Subscribers: kfm-devel, ngraham

Tags: #dolphin

Differential Revision: https://phabricator.kde.org/D23655