fix: modify experimental features to app-level (#6823)

packages/common/env/src/global.ts

@@ -23,6 +23,7 @@ export const runtimeFlagsSchema = z.object({
   enableEnhanceShareMode: z.boolean(),
   enablePayment: z.boolean(),
   enablePageHistory: z.boolean(),
+  enableExperimentalFeature: z.boolean(),
   allowLocalWorkspace: z.boolean(),
   // this is for the electron app
   serverUrlPrefix: z.string(),