Inherit default style for popups

[SfinxNT]

The current setup can cause style inconsistencies between popups and other windows/elements, particularly when using transparent backgrounds.

This change will resolve that issue (popups will inherit default colors for foreground and background).

Since this plugin doesn't utilize window-active-style or menu-style, there's no need for popup-style either.

[SfinxNT]

Before:

After:

[bl11y]

bump

I came from trying to get tmux sessionx manager to be transparent

Hi, sorry for the ping
@kjnsn can you take a look when you get a chance

Appreciate all the work