Fix PHP warning on is_cloudinary_url method

[gabrielcld2]

Fixes #1146

Approach

• Verify the host part of the URL being checked is set
• This prevents any PHP warning being emitted for a few specific URL formats

QA notes

• Turn on WP debug logging by adding the following to your wp-config.php:

define( 'WP_DEBUG', true );
define( 'WP_DEBUG_LOG', true );

• Add the following one-liner to either your theme, or within a plugin:

add_action( 'admin_init', fn() => \Cloudinary\get_plugin_instance()->get_component( 'media' )->is_cloudinary_url( 'mailto:test@example.com' ) );

• Open the WP admin in your browser
  • without this fix, your wp-content/debug.log file should contain a warning like this one: PHP Warning: Undefined array key "host"
  • with this fix, the warning should be gone