♻️ refactor(agora): clean up commented code in token service

- remove commented line for AGORA_APP_SECRET that was no longer in use
- keep only active primary certificate configuration using AGORA_PRIMARY_CERT

src/server/modules/agora/agora-token.service.ts

@@ -8,7 +8,6 @@ export class AgoraTokenService {
 
   constructor() {
     this.appId = process.env.AGORA_APP_ID || ''
-    // this.primaryCert = process.env.AGORA_APP_SECRET || ''
     this.primaryCert = process.env.AGORA_PRIMARY_CERT || ''
     this.tokenExpiry = parseInt(process.env.AGORA_TOKEN_EXPIRY || '3600')