fix ringing sound for in release builds

package.json

@@ -314,6 +314,7 @@
       "certificates/**",
       "images/**",
       "fonts/*",
+      "sound/*",
       "build/assets",
       "node_modules/**",
       "!node_modules/emoji-panel/dist/*",

ts/session/utils/RingingManager.ts

@@ -1,4 +1,4 @@
-const sound = './fixtures/ringing.mp3';
+const sound = './sound/ringing.mp3';
 
 let currentlyRinging = false;