[Enhancement] Allow multiple custom buttons to be displayed on the player interface

[Moyikc]

Currently, only one primary button can be set on the player interface, and the rest must be called from "More", which is not very convenient. In fact, there is still a lot of space on the screen that can be used (you can even add another row to place custom buttons, or automatically reduce the width of each custom button when there are many).

I think there shouldn't be limit on the number of custom buttons added to the player interface.