Define shortcuts for Find actions also for konsolepart

Summary:
The find action in Yakuake (and other konsolepart users) is missing
a shortcut. This is because the shortcut is only defined for Konsole
and not for the part.

BUG: 313841

Test Plan: Press Ctrl + Shift + F in Yakuake, search bar opens

Reviewers: #konsole, hindenburg, hein

Reviewed By: #konsole, hindenburg

Subscribers: konsole-devel

Tags: #konsole

Differential Revision: https://phabricator.kde.org/D19451