Ignore invalid numbers when saving widget settings

When setting to "" or "0" it would error out. It's not really worth it
returning proper errors, as it returns HTML and we'd have to do some
special-fu for that. Just ignoring is okay, and better than "Could not
load /user/dashboard/0".

settings.go

@@ -519,11 +519,10 @@ func (w Widget) SetSetting(ctx context.Context, widget, setting, value string) e
 	}
 	switch def.Type {
 	case "number":
-		n, err := strconv.Atoi(value)
-		if err != nil {
-			return fmt.Errorf("Widget.SetSetting: setting %q for widget %q: %w", setting, widget, err)
+		n, _ := strconv.Atoi(value)
+		if n > 0 {
+			s[setting] = float64(n)
 		}
-		s[setting] = float64(n)
 	case "checkbox":
 		s[setting] = value == "on"
 	case "text", "select":