chore: remove lightningcss from optional peer dep

it's now a dep

Author: sapphi-red

packages/vite/package.json

@@ -159,7 +159,6 @@
     "esbuild": "^0.24.0",
     "jiti": ">=1.21.0",
     "less": "*",
-    "lightningcss": "^1.21.0",
     "sass": "*",
     "sass-embedded": "*",
     "stylus": "*",
@@ -193,9 +192,6 @@
     "sugarss": {
       "optional": true
     },
-    "lightningcss": {
-      "optional": true
-    },
     "terser": {
       "optional": true
     },