Apply script tag escaping in case of <script

Author: sirreal

src/wp-includes/html-api/class-wp-html-tag-processor.php

@@ -3735,7 +3735,10 @@ public function set_modifiable_text( string $plaintext_content ): bool {
 				 * properly escape these things, but this could mask regex patterns
 				 * that previously worked. Resolve this by not sending `</script`
 				 */
-				if ( false !== stripos( $plaintext_content, '</script' ) ) {
+				if (
+					false !== stripos( $plaintext_content, '</script' ) ||
+					false !== stripos( $plaintext_content, '<script' )
+				) {
 					/*
 					 * JavaScript can be safely escaped.
 					 * Non-JavaScript script tags have unknown semantics.