chore(#MagSettingsPanel): adjust SeekBarWithIconButtonsView callbacks

Originally, when clicking icon start/end on view, it would trigger seekbar.setProgress, then the seekbar will update position then trigger callback onProgressChanged with parameter fromUser false. This should be considered as user triggered action too. Therefore, we add new flag mSetProgressFromButtonFlag to help check if the progress changed is triggered by clicking icon button. If the flag is set, SeekBarWithIconButtonsViews would trigger onProgressChanged with parameter fromUser true. Beside, we extend OnSeekBarChangeListener to new interface OnSeekBarWithIconButtonsChangeListener and add method onUserInteractionFinalized in the interface. With the new method, outside listeners can distinguish whether the seekbar progress changed is trigger by dragging the slider or cliking the button.

Bug: 286176069
Test: manually
      atest SeekBarWithIconButtonsViewTest
      atest FontScalingDialogTest
      atest WindowMagnificationSettingsTest
Change-Id: Ibb579a543e5c9286ed88faba8eef5d67f5a902f1