Script Loader: Replace hardcoded output of style tags with calls to wp_add_inline_style.

In this commit, enhancements have been made by replacing manually constructed style tags with calls to `wp_add_inline_style`. Previously, numerous style tags were generated and output directly in the header, resulting in redundant code and bypassing the core's style enqueueing system. This approach made it challenging for third-party developers to manage and control the output of these style tags.

To ensure backward compatibility, the following functions have been deprecated and replaced:

- print_embed_styles
- print_emoji_styles
- wp_admin_bar_header
- _admin_bar_bump_cb

Backward compatibility shims have also been added, ensuring that if these functions were previously unhooked from there actions, they will continue to not output a style tag.

However, for the following functions, conversion to use inline styles was not feasible due to the potential disruption it might cause by changing the style tag IDs, potentially breaking JavaScript functionality for a number of plugins in the repository:

- custom-background
- wp-custom

These changes improve code maintainability and enhance the flexibility and control available to developers when managing style outputs within WordPress core.

Props spacedmonkey, hlunter, westonruter, flixos90.
Fixes #58775.

git-svn-id: https://develop.svn.wordpress.org/trunk@56682 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/embed.php

@@ -1059,18 +1059,22 @@ function enqueue_embed_scripts() {
 }
 
 /**
- * Prints the CSS in the embed iframe header.
+ * Enqueues the CSS in the embed iframe header.
  *
- * @since 4.4.0
+ * @since 6.4.0
  */
-function print_embed_styles() {
-	$type_attr = current_theme_supports( 'html5', 'style' ) ? '' : ' type="text/css"';
-	$suffix    = SCRIPT_DEBUG ? '' : '.min';
-	?>
-	<style<?php echo $type_attr; ?>>
-		<?php echo file_get_contents( ABSPATH . WPINC . "/css/wp-embed-template$suffix.css" ); ?>
-	</style>
-	<?php
+function wp_enqueue_embed_styles() {
+	// Back-compat for plugins that disable functionality by unhooking this action.
+	if ( ! has_action( 'embed_head', 'print_embed_styles' ) ) {
+		return;
+	}
+	remove_action( 'embed_head', 'print_embed_styles' );
+
+	$suffix = wp_scripts_get_suffix();
+	$handle = 'wp-embed-template';
+	wp_register_style( $handle, false );
+	wp_add_inline_style( $handle, file_get_contents( ABSPATH . WPINC . "/css/wp-embed-template$suffix.css" ) );
+	wp_enqueue_style( $handle );
 }
 
 /**