docs(pos): fix Storage.current jsdoc — reference set/delete, not update

The Storage interface does not expose an update() method (only
set/get/clear/delete/entries). Replace the stale 'update()' reference
with 'delete()' so the docs match the actual API surface.

Author: vctrchu

packages/ui-extensions/src/surfaces/point-of-sale/types/storage.ts

@@ -24,7 +24,7 @@ export interface Storage<
    *
    * Each key is exposed as a `ReadonlySignalLike<T | undefined>`, enabling cross-target
    * reactivity. One extension target can subscribe to a key and react when
-   * another target updates it via `set()` or `update()`.
+   * another target updates it via `set()` or `delete()`.
    *
    * The `value` property provides synchronous access to the current stored value.
    * The `subscribe()` method registers a callback that fires whenever the value