fix: auto routes incorrectly display route filters with GET method

[kenjis]

Description
Follow-up #5628

• auto routes incorrectly display route filters with GET method

--- a/app/Config/Routes.php
+++ b/app/Config/Routes.php
@@ -31,7 +31,7 @@ $routes->setAutoRoute(true);
 
 // We get a performance increase by specifying the default
 // route since we don't have to scan directories.
-$routes->get('/', 'Home::index');
+$routes->get('/', 'Home::index', ['filter' => 'csrf'] );
 
 /*
  * --------------------------------------------------------------------

Before:

+--------+------------------+------------------------------------------+----------------+---------------+
| Method | Route            | Handler                                  | Before Filters | After Filters |
+--------+------------------+------------------------------------------+----------------+---------------+
| GET    | /                | \App\Controllers\Home::index             | csrf           | csrf toolbar  |
| CLI    | ci(.*)           | \CodeIgniter\CLI\CommandRunner::index/$1 |                |               |
| auto   | /                | \App\Controllers\Home::index             | csrf           | csrf toolbar  |
| auto   | home             | \App\Controllers\Home::index             |                | toolbar       |
| auto   | home/index[/...] | \App\Controllers\Home::index             |                | toolbar       |
+--------+------------------+------------------------------------------+----------------+---------------+

• The auto route / does not reach when GET.
• It can be accessible when POST/PUT/..., but it has no filters actually.

After:

+--------+------------------+------------------------------------------+----------------+---------------+
| Method | Route            | Handler                                  | Before Filters | After Filters |
+--------+------------------+------------------------------------------+----------------+---------------+
| GET    | /                | \App\Controllers\Home::index             | csrf           | csrf toolbar  |
| CLI    | ci(.*)           | \CodeIgniter\CLI\CommandRunner::index/$1 |                |               |
| auto   | /                | \App\Controllers\Home::index             |                | toolbar       |
| auto   | home             | \App\Controllers\Home::index             |                | toolbar       |
| auto   | home/index[/...] | \App\Controllers\Home::index             |                | toolbar       |
+--------+------------------+------------------------------------------+----------------+---------------+

Checklist:

• Securely signed commits
• [] Component(s) with PHPDoc blocks, only if necessary or adds value
• Unit testing, with >80% coverage
• [] User guide updated
• Conforms to style guide