[Konqueror] Remove KonqView::setActiveComponent()

Summary:
It's mostly redundant since KF5 port; the remaining bit
m_activityResourceInstance->notifyFocusedIn() call can be moved to
KonqView::eventFilter().

Test Plan: It compiles, koqueror still loads.

Reviewers: dfaure, stefanocrocco

Reviewed By: dfaure

Subscribers: kde-frameworks-devel

Differential Revision: https://phabricator.kde.org/D24793