As I mentioned at the beginning of my new WR video, I've accidentally found a skip that forces the game to end all dialogues automatically almost about a second after they appear (in the fast forward mode). As you can see, textboxes in the top right corner disappear without clicking the checkmark button. To set up the skip before launching the game you have to disable all audio output devices in your system (turning the volume to 0 won't do the job).
It doesn't trigger every time though. You can check if it works by starting any of the campaign missions - if the mission intro text disappears immediately, it's ok. If it stops on the first line of the intro, you have to restart the game. The skip works in whole game and once it triggers, it works as long as you have the game on.
You have to play the game in total silence but it's a huge timesave, especially that it cuts all of the annoyance that comes with moving your mouse to that top right corner all the time, so in my opinion it's worth its' price.
Feel free to ask any further questions and test it yourselves :)