T.MaxFPS not restored when exiting PIE while Fixed Frame Interval Playback is enabled

T.MaxFPS not restored when exiting PIE while Fixed Frame Interval Playback is enabled

Regression: YES
Directly related to CL:3365017, it would seem.
Broken: 4.16
Worked: 4.15

1. Create a basic sequence and set it to auto-play in the level
2. Set the Playback speed to 15 fps
3. Enable "Force Fixed Frame Interval Playback" in the Sequence editor
4. PIE
5. Before the sequence finishes, exit PIE (escape key)
6. Bring up the output log and type "t.maxfps"

Result: t.maxfps is still set to 15
Expected: Returns to 0 or whatever the editor was set to previously