obs-webrtc: Fix legacy CMake obs_status call

An additional stray comma resulted in an incorrectly formatted status
message in the CMake log.

plugins/obs-webrtc/cmake/legacy.cmake

@@ -2,7 +2,7 @@ project(obs-webrtc)
 
 option(ENABLE_WEBRTC "Enable WebRTC Output support" ON)
 if(NOT ENABLE_WEBRTC)
-  obs_status(DISABLED, "obs-webrtc")
+  obs_status(DISABLED "obs-webrtc")
   return()
 endif()