Block Editor: Remove the .is-dark-theme body class from the admin h…

…eader.

With the changes to dark theme support in WordPress/gutenberg#28233 to check the real background color of the theme, this no longer serves any purpose.

Follow-up to [44133].

Props scruffian, sabernhardt.
Fixes #52385.

git-svn-id: https://develop.svn.wordpress.org/trunk@50142 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-admin/admin-header.php

@@ -192,10 +192,6 @@
 if ( $current_screen->is_block_editor() ) {
 	// Default to is-fullscreen-mode to avoid jumps in the UI.
 	$admin_body_class .= ' block-editor-page is-fullscreen-mode wp-embed-responsive';
-
-	if ( current_theme_supports( 'editor-styles' ) && current_theme_supports( 'dark-editor-style' ) ) {
-		$admin_body_class .= ' is-dark-theme';
-	}
 }
 
 $error_get_last = error_get_last();