Option to acquire the guiding status from PHD2 to stay in sync

Summary:
Due to concurrency in PHD2 it might happen, that a last guiding step is executed after a pause command has been successfully executed. This can create problems with the Guide module, since the Guide module assumes automatically being in state GUIDE_GUIDING if it sees a guiding step.
To resolve this, the PHD2 module no longer guesses the state but it re-aquires it from PHD2.

This method could be used in future in other situations as well. Due to try to avoid any regressions, I only resolved this single code place. If it turns out to be stable, we could refactor other places as well.

Test Plan: This specific situation is difficult to test. Since a central method handling a received state information has been refactored, please test all situations where PHD2 changes its state.

Reviewers: mutlaqja, TallFurryMan, lancaster

Reviewed By: mutlaqja

Subscribers: kde-edu

Tags: KDE Edu

Differential Revision: https://phabricator.kde.org/D28788