allow_development_packages does not fix DISPATCHER_MISSING_REQUIRED_PACKAGE — HAProxyApplyDispatcher was missed in #877 fix #905

Describe the bug
Commit 7c7da25 added the allow_development_packages setting which correctly fixes the package check in Core/Model.inc. But, Dispatchers/HAProxyApplyDispatcher.inc has its own separate $required_packages check that was not updated and is unaffected by the setting.

With allow_development_packages enabled and pfSense-pkg-haproxy-devel installed, POST /api/v2/services/haproxy/apply still returns:

  {
    "code": 424,
    "response_id": "DISPATCHER_MISSING_REQUIRED_PACKAGE",
    "message": "The requested action requires the `pfSense-pkg-haproxy` package but it is not installed."
  }

The file still contains:
protected array $required_packages = ['pfSense-pkg-haproxy'];

This was identified in #877 (Dispatchers/HAProxyApplyDispatcher.inc:13) but was not included in the fix. The Core/Dispatcher.inc package check logic also needs to respect the allow_development_packages setting, the same way Core/Model.inc now does.

To Reproduce

1. Install pfSense-pkg-haproxy-devel (not the standard pfSense-pkg-haproxy)
2. Install pfSense-pkg-RESTAPI v2.8.0
3. Navigate to System > REST API > Settings > Advanced Settings, enable Allow Development Packages, and save
4. Make a POST request to /api/v2/services/haproxy/apply

** Expected behavior**
The request should work. allow_development_packages is enabled and the -devel variant of the required package is installed, so the dependency check should pass — consistent with how Core/Model.inc now behaves after the fix in #877.

Response

  {
    "code": 424,
    "status": "failed dependency",
    "response_id": "DISPATCHER_MISSING_REQUIRED_PACKAGE",
    "message": "The requested action requires the `pfSense-pkg-haproxy` package but it is not installed.",
    "data": [] 
  }

pfSense Version & Package Version:

• pfSense Version: 26.03.1-RELEASE
• Package Version: v2.8.0

Affected Endpoints:

• POST /api/v2/services/haproxy/apply
• Others as described in HAProxy models reject pfSense-pkg-haproxy-devel in REQUIRED_PACKAGES check #877

Additional context
Issue #877 correctly identified Dispatchers/HAProxyApplyDispatcher.inc:13 as one of the affected files, but commit 7c7da25 only updated Core/Model.inc. The Dispatcher has its own independent $required_packages check that is not gated by the allow_development_packages setting. The Model layer is fixed; the Dispatcher layer is not.

Issue #877 's local workaround now only needs to update the dispatcher.