remove unused transfer secret from app provider

changelog/unreleased/fix-app-provider-unused-transfer-secret.md

@@ -0,0 +1,8 @@
+Bugfix: Remove unused transfer secret from app provider
+
+We've fixed the startup of the app provider by removing the startup dependency
+on a configured transfer secret, which was not used. This only happend if you
+start the app provider without runtime (eg. `ocis app-provider server`) and didn't
+have configured all oCIS secrets.
+
+https://github.com/owncloud/ocis/pull/3798

extensions/app-registry/pkg/config/parser/parse.go

@@ -38,9 +38,5 @@ func Validate(cfg *config.Config) error {
 		return shared.MissingJWTTokenError(cfg.Service.Name)
 	}
 
-	if cfg.TransferSecret == "" {
-		return shared.MissingRevaTransferSecretError(cfg.Service.Name)
-	}
-
 	return nil
 }