Share env vars client-side using @Public decorator (#6627)

* fix: public env vars using decorator

* fix: relocate

* fix: use env.public

* fix: register public env vars across plugins

* fix: test

* fix: tsc

* fix: mark remaining ones as public

* fix: move oidc ones to plugin

* fix: prevent overwrite

* fix: review

shared/utils/urls.ts

@@ -9,7 +9,7 @@ import { RESERVED_SUBDOMAINS, getBaseDomain, parseDomain } from "./domains";
  * @returns The path with the CDN url prepended.
  */
 export function cdnPath(path: string): string {
-  return `${env.CDN_URL}${path}`;
+  return `${env.CDN_URL ?? ""}${path}`;
 }
 
 /**