feat(video): add ESC key support to skip campaign Bink videos

[bobtista]

-Closes #1896

Adds the ability to skip campaign Bink videos by pressing ESC, matching the behavior of other movies in the game.

Changes:

• Added isVideoPlaying() and skipVideo() methods to SinglePlayerLoadScreen
• Updated video playback loops to check for skip requests and exit early when ESC is pressed
• Updated ESC key handler in WindowXlat to detect campaign videos and trigger skip

Tested with Zero Hour USA Solo Play intro video.

[xezon]

The edits between Generals and Zero Hour need to be properly synced.

[xezon]

Does not compile :P

[bobtista]

Does not compile :P

Fixed :)

[xezon]

I think this review never get done :)

[xezon]

After taking a look at this function, I think this logic can be greatly simplified by cutting the Message middle man and do the key press detection right in this update loop, which then eliminates touching a whole bunch of files.

[xezon]

I can take over this change because it takes too many revisions to review.