Cannot override editor shortcut bindings on Linux

Clicking the Override option when attempting to replace a keyboard shortcut with another key that is already bound will not update the settings.

Workaround:
Unbinding the key before rebinding it to the new shortcut will allow the new setting to be accepted.

Regression:
No - The same behavior exists in 4.13.2

1. Open UE4 Editor (any project)
2. Open Editor Preferences
3. Type "Navigation" into the search bar
4. Under Viewport Navigation, change key for Forward (W) to Z
5. In the pop up window, click Override

Result:
Pop up window closes but shortcut setting is unchanged

Expected:
Z is set as Forward and FOV Zoom Out becomes unassigned