Push gateway config (#4608)

* Read PushProvidersConfig parameter from BuildTimeConfig

* Update submodule link.

plugins/src/main/kotlin/config/BuildTimeConfig.kt

@@ -31,4 +31,7 @@ object BuildTimeConfig {
     val SERVICES_SENTRY_DSN: String? = null
     val BUG_REPORT_URL: String? = null
     val BUG_REPORT_APP_NAME: String? = null
+
+    const val PUSH_CONFIG_INCLUDE_FIREBASE = true
+    const val PUSH_CONFIG_INCLUDE_UNIFIED_PUSH = true
 }