Fix a couple of issues with a feeds (#14897)

@CirnoT spotted a couple of issues with feeds on discord.

This PR fixes both of these.

modules/templates/helper.go

@@ -817,6 +817,10 @@ func ActionIcon(opType models.ActionType) string {
 func ActionContent2Commits(act Actioner) *repository.PushCommits {
 	push := repository.NewPushCommits()
 
+	if act == nil || act.GetContent() == "" {
+		return push
+	}
+
 	json := jsoniter.ConfigCompatibleWithStandardLibrary
 	if err := json.Unmarshal([]byte(act.GetContent()), push); err != nil {
 		log.Error("json.Unmarshal:\n%s\nERROR: %v", act.GetContent(), err)