v1.0.1 - Hotfix: delay adding right click option

Users were occasionally seeing the following error, possibly due to the addon trying to override the voice button's right click option too early.

I have put in a minor change to wait 2s before trying to override the button.
I have also added a check, so if we end up trying to add it too early, errors won't happen.

[volume_slider] addons/volume_slider/lua/autorun/client/cl_scoreboard_voicesliders.lua:115: attempt to index field 'voice' (a nil value)
  1. unknown - addons/volume_slider/lua/autorun/client/cl_scoreboard_voicesliders.lua:115

Timer Failed! [Simple][@addons/volume_slider/lua/autorun/client/cl_scoreboard_voicesliders.lua (line 106)]

v1.0.0 - Initial release

Adds the initial version of the volume slider.

Get it on the workshop - https://steamcommunity.com/sharedfiles/filedetails/?id=2510453372