[BUGFIX] Handle wrong package path calculation for extension development

Can be reverted once https://review.typo3.org/c/Packages/TYPO3.CMS/+/85212
is merged and released.

Tests/Build/Scripts/fix_invalid_package_path.sh

@@ -0,0 +1,16 @@
+#!/usr/bin/env bash
+# shellcheck disable=SC2155,SC2059
+set -e
+
+readonly artifactFile=".Build/vendor/typo3/PackageArtifact.php"
+readonly tempFile="$(mktemp)"
+
+CYAN="\e[36m"
+YELLOW="\e[43m"
+NC="\e[0m"
+
+printf "${YELLOW}Running script to fix invalid package path in PackageArtifact.${NC}\n"
+printf "${CYAN}Please remove this script once https://review.typo3.org/c/Packages/TYPO3.CMS/+/85212 is released.${NC}\n"
+
+awk '{ gsub(/packagePath";s:2:"\/\/"/, "packagePath\";s:0:\"\""); print }' "$artifactFile" > "$tempFile" \
+    && mv "$tempFile" "$artifactFile"

composer.json

@@ -88,7 +88,8 @@
 			"@composer -d Tests/CGL update"
 		],
 		"post-autoload-dump": [
-			"@environment:prepare"
+			"@environment:prepare",
+			"Tests/Build/Scripts/fix_invalid_package_path.sh"
 		],
 		"cgl": "@composer -d Tests/CGL --",
 		"docs": [