fix(web): fixes devserver allowed hosts option schema validation error

I removed `enum` to fix `--allowed-hosts` option schema validation error. snum should be removed so
developers have the option to pass whatever they want. it was a mistake from
#1969 PR.

packages/web/src/builders/dev-server/schema.json

@@ -51,8 +51,7 @@
     },
     "allowedHosts": {
       "type": "string",
-      "description": "This option allows you to whitelist services that are allowed to access the dev server.",
-      "enum": ["host.com,host2.com", ".host.com"]
+      "description": "This option allows you to whitelist services that are allowed to access the dev server."
     }
   }
 }