Do not embed styles.css from library demo directory

Problem/Motivation

The styles.css embeeded from tiny_slider.libraries.yml doesn't use any specific selector and break the global site style.

Steps to reproduce

Enable the tiny_slider module, create a slider block with views UI and use the block layout UI to place it.

Proposed resolution

Build a specific styles.css and embed it with specific selector (.tns-outer for example) instead of the one provided by the library.

If the change cannot be done, we can simply use the libraries-override keyword in the [theme].info.yml like this :

libraries-override:
  tiny_slider/tiny_slider:
    css:
      theme:
        /libraries/tiny-slider/demo/css/styles.css: false

To remove the styles.css load.