Fixes symfony#2901 - [Autocomplete] - Asset mapper installs wrong css file

Explicitly add missign css files defined in package.json

Relates to: symfony#2901

Author: leevigraham

src/Autocomplete/assets/package.json

@@ -37,7 +37,10 @@
         },
         "importmap": {
             "@hotwired/stimulus": "^3.0.0",
-            "tom-select": "^2.2.2"
+            "tom-select": "^2.2.2",
+            "tom-select/dist/css/tom-select.default.css": "^2.2.2",
+            "tom-select/dist/css/tom-select.bootstrap4.css": "^2.2.2",
+            "tom-select/dist/css/tom-select.bootstrap5.css": "^2.2.2"
         }
     },
     "peerDependencies": {