Allow Window Resize has no effect on Linux

Checking the option for Allow Window Resize in Project Settings allows a the borders of a standalone window to be grabbed and used to resize the window. This does not behave the same on Linux and the standalone window cannot be adjusted.

Suggested Fix:
User reported changing LinuxWindow.cpp (line 104 in 4.16.1) to the following will make Allow Window Resize to work on Linux

if ( !Definition->HasOSWindowBorder )
 {
     WindowStyle |= SDL_WINDOW_BORDERLESS;
 }
 
 if (Definition->IsTopmostWindow)
 {
     WindowStyle |= SDL_WINDOW_ALWAYS_ON_TOP;
 }
 
 if (!Definition->AppearsInTaskbar)
 {
     WindowStyle |= SDL_WINDOW_SKIP_TASKBAR;
 }
 
 if (Definition->IsRegularWindow && Definition->HasSizingFrame)
 {
     WindowStyle |= SDL_WINDOW_RESIZABLE;
 }

1. Open UE4 Editor (any project) on Linux
2. Search "resize" in Project Settings
3. Check the box for Allow Window Resize
4. Run project in standalone
5. Press tilde to access the mouse
6. Use the mouse to grab the sides of the standalone window

Result:
The mouse does not change to the resize widget and the window cannot be resized

Expected:
The game window can be resized with the mouse when Allow Window Resize is checked