[interactiveconsole] Fix initial load selection
QActionGroup has no signal for when an action within the group changes
checked state. Only when an action within is triggered.
Without calling trigger InteractiveConsole::modeSelectionChanged is not
triggered and m_mode is not updated.
qdbus to launch the console
Execute button went to the right place
Reviewers: Plasma, broulik
Reviewed By: Plasma, broulik
Subscribers: broulik, plasma-devel
Differential Revision: https://phabricator.kde.org/D21852