Making the viewport fullscreen while Application scale is a value other than 1.0 results in a zoomed in/out viewport

When using Application Scale in the editor, using F11 to make the viewport fullscreen results in an either zoomed in or zoomed out fullscreen version.

Note: This same issue occurs when using a combination of UI scaling in windows 10 and "-enablehighdpi"

Regression?: No
This also occurred in 4.13

1. Open a project
2. Set the application scale to a value other than 1.0 (Window > Developer Tools > Widget Reflector > Application Scale at the top left)
3. Click on the editor's viewport
4. Press F11
   Result: The viewport becomes zoomed in (if scale is over 1.0) or zoomed out (if scale is under 1.0) and doesn't adhere to the screen correctly
   Expected: The viewport becomes fullscreen as expected