[12.x] Add wildcard pattern support to TrimStrings middleware

[overtrue]

This PR adds wildcard pattern support to the TrimStrings middleware's $except array, so we can skip trimming for nested request parameters like foo.bar.*.name.

Background

We need to trim strings globally, but some interfaces require preserving whitespace as valid input. The current shouldSkip method uses in_array($key, $except, true) which only does exact matching, so you can't use patterns like users.*.email to exclude nested fields.

This was requested in #48212 and #50901.

Changes

Changed shouldSkip to use Str::is() instead of in_array(), which supports Laravel's wildcard patterns. This lets you use TrimStrings::except() to define exceptions for nested fields that need to preserve whitespace.

Backward compatible - exact matches still work the same way.

Usage

You can use wildcard patterns in two ways:

Via TrimStrings::except():

// In AppServiceProvider
TrimStrings::except([
    'users.*.name',
    'orders.*.items.*.meta.title',
    'orders.*.items.*.meta.tags.*',
]);

Or in a custom middleware:

class TrimStrings extends Middleware
{
    protected $except = [
        'users.*.name',
        'orders.*.items.*.meta.title',
        'orders.*.items.*.meta.tags.*',
    ];
}