UI <=> Background - Initialize UI without waiting for background connection

**Epic: Allow the UI to read state from the storage system**
https://github.com/MetaMask/metamask-extension/issues/18054

We will need to boot the UI application without waiting for the service worker, which can be handled in the app/scripts/ui.js file.
You can refer to this [POC](https://github.com/MetaMask/metamask-extension/pull/17635/files) for implementation.

**Tasks**:
-`updateUiStreams` without waiting for `isUIInitialised`

Start in app/scripts/ui.js and compare the implementation with the linked POC in pull request 17635. Trace updateUiStreams and its dependency on isUIInitialised, then verify that the UI boots without waiting for the service worker connection while still updating its streams.

Written by the indexing model from the issue text.