SDC: component library not alterable

Problem/Motivation

When a component declare a library, its path is made relative to core because https://git.drupalcode.org/project/drupal/-/blob/11.x/core/lib/Drupal/Co...

/**
   * Takes a path and makes it relative to the library provider.
   *
   * Drupal will take a path relative to the library provider in order to put
   * CSS and JS in the HTML page. Core is the provider for all the
   * auto-generated libraries for the components. This means that in order to
   * add <root>/themes/custom/my_theme/components/my-component/my-component.css
   * in the page, we need to crawl back up from <root>/core first:
   * ../themes/custom/my_theme/components/my-component/my-component.css.
   *
   * @param string $path
   *   The path to the file.
   *
   * @return string
   *   The path relative to the library provider root.
   */
  private function makePathRelativeToLibraryRoot(string $path): string {
    $path_from_root = str_starts_with($path, $this->appRoot)
      ? substr($path, strlen($this->appRoot) + 1)
      : $path;
    // The library owner is in <root>/core, so we need to go one level up to
    // find the app root.
    return '../' . $path_from_root;
  }

Currently, it is not possible to a theme to alter a component library with its .info.yml file.

For example, the following code will not work (.info.yml of the theme):

libraries-override:
  core/components.my_theme--navbar:
    css:
      component:
        styles/navbar.css: false or replace

Because the path to the file when debugging library alteration is:

../path/to/my_theme/components/navbar/styles/navbar.css

So the CSS is not removed/replaced. It should be:

libraries-override:
  core/components.my_theme--navbar:
    css:
      component:
        ../path/to/my_theme/components/navbar/styles/navbar.css: false or replace

Which can't be relied on when preparing if the theme will be gathered as a Composer package and so placed potentially in a contrib folder and not a custom folder like on the env used to develop it.

Steps to reproduce

Proposed resolution

Either:
- the provider should be the module/theme declaring the component
- the path should not depend on the path of the Drupal extension
- in the library override processing, when searching for matches, concat with the extension path automatically?

Remaining tasks

API changes