[TASK] Allow Piwik PRO debug mode param '_stg_debug'

The URL param '_stg_debug' is needed to call the debug mode on-site

Resolves: #101613
Releases: main, 11.5, 12.4
Change-Id: Iff94ede5c3d388fe8b130e10e5b48658511a0bc3
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/80473


Tested-by: Stefan B�rk <stefan@buerk.tech>
Reviewed-by: Stefan B�rk <stefan@buerk.tech>
Tested-by: core-ci <typo3@b13.com>

typo3/sysext/core/Configuration/DefaultConfiguration.php

@@ -1456,6 +1456,7 @@ return [
                 // Piwik
                 'pk_campaign',
                 'pk_kwd',
+                '_stg_debug',
                 // Google
                 'utm_source',
                 'utm_medium',