Install: reset button does not work at stage 2

This was caused by the install.js scripts only being loaded at stage 1.

Fixes #26664

admin/install.php

@@ -139,7 +139,7 @@ function_exists( 'mysqli_stmt_get_result' ),
 
 layout_page_header_begin( 'Administration - Installation' );
 # Javascript is only needed to support input of installation options
-if( $t_install_state < 2 ) {
+if( $t_install_state <= 2 ) {
 	html_javascript_link( 'install.js' );
 }
 layout_page_header_end();