fix(bundle): fix vite build

Some bundlers (like vite) do not support having a "browser" field in a
nested package.json.

Note: the previous commit ([1]) fixed the resolution of the "browser"
field in the dev bundle, but the production bundle still failed.

Related: socketio/socket.io-client#1504

[1]: 4971914

Author: darrachequesne

package.json

@@ -86,7 +86,10 @@
     "prepack": "npm run compile"
   },
   "browser": {
-    "./test/node.js": false
+    "./test/node.js": false,
+    "./build/esm/transports/xmlhttprequest.js": "./build/esm/transports/xmlhttprequest.browser.js",
+    "./build/esm/transports/websocket-constructor.js": "./build/esm/transports/websocket-constructor.browser.js",
+    "./build/esm/globalThis.js": "./build/esm/globalThis.browser.js"
   },
   "repository": {
     "type": "git",