Use layouts for QDialogs to make KmPlot adopt the sizes
Summary:
As it was pointed out "KDialog had its own layout, and when porting to QDialog, a layout needs to be added"
BUG: 407980
Test Plan:
- Open KmPlot, choose "Catesian Plot".
- Enter something (e.g. "x^2").
- Click on the Equation Editor button at the right of the input field.
- Try to resize the window (all interface items are movable now).
- Press the Constant Editor button.
- Try to resize the window (all interface items are movable now).
- Close the windows.
- Try to choose any item from the "Tools" menu.
- Try to resize the window (all interface items should be movable).
Reviewers: KDE Edu, cfeck
Reviewed By: cfeck
Subscribers: kde-edu
Tags: KDE Edu
Differential Revision: https://phabricator.kde.org/D21428