[BUGFIX] Correctly apply config.absRefPrefix to _assets resources

When using a composer-based installation, public frontend assets
such as JavaScript of stylesheet files are exposed in a dedicated
`_assets/` folder. In those scenarios TypoScript settings for
`config.absRefPrefix` need to be applied as well.

Resolves: #96452
Releases: main, 11.5
Change-Id: I0695850be18c9c152c647883c122a0680e8e734f
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/72954

Tested-by: core-ci <typo3@b13.com>
Tested-by: Oliver Hader <oliver.hader@typo3.org>
Reviewed-by: Oliver Hader <oliver.hader@typo3.org>

typo3/sysext/frontend/Classes/Controller/TypoScriptFrontendController.php

@@ -3004,12 +3004,14 @@ class TypoScriptFrontendController implements LoggerAwareInterface
             return;
         }
         $search = [
+            '"_assets/',
             '"typo3temp/',
             '"' . PathUtility::stripPathSitePrefix(Environment::getExtensionsPath()) . '/',
             '"' . PathUtility::stripPathSitePrefix(Environment::getBackendPath()) . '/ext/',
             '"' . PathUtility::stripPathSitePrefix(Environment::getFrameworkBasePath()) . '/',
         ];
         $replace = [
+            '"' . $this->absRefPrefix . '_assets/',
             '"' . $this->absRefPrefix . 'typo3temp/',
             '"' . $this->absRefPrefix . PathUtility::stripPathSitePrefix(Environment::getExtensionsPath()) . '/',
             '"' . $this->absRefPrefix . PathUtility::stripPathSitePrefix(Environment::getBackendPath()) . '/ext/',