fix(@angular-devkit/build-angular): upgrade postcss to 8.5.23

This addresses GHSA-fxqj-rqcc-2cmp

Author: alan-agius4

packages/angular/build/package.json

@@ -56,7 +56,7 @@
     "jsdom": "29.1.1",
     "less": "4.6.7",
     "ng-packagr": "22.1.0",
-    "postcss": "8.5.19",
+    "postcss": "8.5.23",
     "rollup": "4.62.2",
     "rxjs": "7.8.2",
     "vitest": "4.1.10"

packages/angular_devkit/build_angular/package.json

@@ -42,7 +42,7 @@
     "ora": "9.4.1",
     "picomatch": "4.0.5",
     "piscina": "5.2.0",
-    "postcss": "8.5.19",
+    "postcss": "8.5.23",
     "postcss-loader": "8.2.1",
     "resolve-url-loader": "5.0.0",
     "rxjs": "7.8.2",