Time snapping interval is not updating the timeline in UMG Sequencer

Changing the time snapping interval in UMG Sequencer doesn't seem to update the timeline. It appears to stay as though it is being snapped by time rather than frames.

This is a Regression from 4.15 @ CL 3257883

1. Open QAGame
2. Open Test-Animation UMG
3. Add a new animation by selecting the + Animation button in the Animations tab
4. Select the newly created animation
5. In the Timeline tab, change the Time Snapping Interval to 30FPS

Result: The Timeline stays the same and shows time rather than frames

Expected Result: The Timeline updates and it shows the frames rather than the time