Add left_click_sound to LuaStyle

[jdogg]

Was wondering if this would be possible so I could change the sound file of the the style through the control script.

The idea being if the player can't reach the entity my GUI is trying access it plays the default cannot-build.ogg but if they can it just uses the normal gui-click.ogg sound. I can get it to kinda work by making two different gui styles with the different sound files but when the script updates the style it doesn't use the new style's left_click_sound file. This means the player has to click the button twice to get the error sound. Not terrible, but doesn't feel right.

Unless there is some other way to access this that I'm not seeing.