Improves notify props validation (#24031)

* Adds the channel member notify props max runes restriction

* Fix translations

server/channels/app/channel.go

@@ -1338,14 +1338,17 @@ func (a *App) UpdateChannelMemberNotifyProps(c request.CTX, data map[string]stri
 	member, err := a.Srv().Store().Channel().UpdateMemberNotifyProps(channelID, userID, filteredProps)
 	if err != nil {
 		var appErr *model.AppError
+		var invErr *store.ErrInvalidInput
 		var nfErr *store.ErrNotFound
 		switch {
 		case errors.As(err, &appErr):
 			return nil, appErr
+		case errors.As(err, &invErr):
+			return nil, model.NewAppError("updateMemberNotifyProps", "app.channel.update_member.notify_props_limit_exceeded.app_error", nil, "", http.StatusBadRequest).Wrap(err)
 		case errors.As(err, &nfErr):
 			return nil, model.NewAppError("updateMemberNotifyProps", MissingChannelMemberError, nil, "", http.StatusNotFound).Wrap(err)
 		default:
-			return nil, model.NewAppError("updateMemberNotifyProps", "app.channel.get_member.app_error", nil, "", http.StatusInternalServerError).Wrap(err)
+			return nil, model.NewAppError("updateMemberNotifyProps", "app.channel.update_member.app_error", nil, "", http.StatusInternalServerError).Wrap(err)
 		}
 	}
 

server/channels/app/export.go

@@ -390,7 +390,6 @@ func (a *App) buildUserChannelMemberships(userID string, teamID string) (*[]impo
 }
 
 func (a *App) buildUserNotifyProps(notifyProps model.StringMap) *imports.UserNotifyPropsImportData {
-
 	getProp := func(key string) *string {
 		if v, ok := notifyProps[key]; ok {
 			return &v