That's a powerful PC for sure, for video editing it is mostly 2D work rather than 3D so video editing does not need the level of performance of a games graphics card. For Adobe photoshop certain functions do make use of graphics card acceleration, namely, for a graphics card that supports OpenGL, a software and hardware standard that accelerates video processing when working with large or complex images, including 3D., will benefit. However to what extent this help compared with processing done in the CPU is questionable. So you have to read up here enter link description hereto see what GPU features are relevant to you and this page has links to older versions of Photoshop too. Last but not least, this PC spec that you stated is on the powerful side. If this has been recommended by a shop then you may need to question whether it has been over sold to what you will need to do. But in principle getting the most powerful CPU for your budget is a good rule of thumb as you can always easily upgrade from the cheap graphics card any time. I would suggest that you use the CPU's integrated graphics card to start off. The reason is that unless you know what you will do spending money on a very good graphics card may be wasted. Let me illustrate an example of a special effect that was applied with its default options to a 12MB (38 megapixel) image, making use of GPU accelerated graphics, the integrated graphics HD 4000(at zero additional cost)completed this task in 38 secs and an expensive card finished this same task in 18 secs. Even budget to medium graphics card complete this in around 20-22 secs.
Surface Pro (2017) vs Surface Pro 4