Update time signature style images

[miiizen]

Resolves: #26431

[avvvvve]

@miiizen Could you just add a 1px stroke to the image and round the corners by 3px please?

Also, the contents of this style tab seem to have a fixed width, but let's address that when we update the images for the courtesy options below (which I actually was having issues using today, so I will try again next week).