qml: use radio buttons instead of combo box for presets in playback speed selection popup

Having the presets in a combo box requires one extra click. The combo box (a popup itself) also does not look good within a popup.

I have imported RadioButton.qml from Qt Quick Basic style. The main changes are colorization and sizing.

I also started to close the popup when a preset is selected. Currently changing the combo box current item does not close the popup (annoying).

I have captured these screen shots (spacing slightly different as I have modified after the screenshots taken):

Light, 1x selected, 1.5x visual focus:

Dark, 1x selected, 1.5x pressed:

Before:

I have tested this with Qt 6.2 and 6.8.

Request review @chub.