Update dependency cssnano to v7 (#30061)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

package.json

@@ -66,7 +66,7 @@
     "core-js": "^3.30.2",
     "cross-env": "^7.0.3",
     "css-loader": "^5.2.7",
-    "cssnano": "^6.0.1",
+    "cssnano": "^7.0.0",
     "detect-passive-events": "^2.0.3",
     "emoji-mart": "npm:emoji-mart-lazyload@latest",
     "escape-html": "^1.0.3",