Preload doesn't work if the gallery was initialized with not enough images

[pweerd]

Description

In the situation that you initialize the gallery without images and doing a refresh() afterwards, the preload functionality is not working.
This is caused by a bug in the function normalizeSettings(). This function sets the preload setting to 0 if there were no images.

Of course a reset() afterwards doesn't help, because the setting is already overwritten.

It seems better to do the Math.min check during the preload itself.

Steps to reproduce

1. Initialize the gallery with a nonzero preload, but no images.
2. Refresh the gallery with some images. Now the preload doesn't work.

Sample HTML markup

Environment

• Browser and version - Chrome Version 130.0.6723.117 (Official Build) (64-bit)
• OS - Windows 10
• lightGallery version - 2.7.1

Additional context