bug(Listbox): Can not select first option with Enter after calling .goToFirst() (@angular/aria)

### Is this a regression?

- [ ] Yes, this behavior used to work in the previous version

### The previous version in which this bug was not present was

_No response_

### Description

When calling `.goToFirst()` the first option is set active. But it is not possible to select it with _Enter_. If the user hits _arrow down_ one time you can select the first option. But my whole reason for calling `.goToFirst()` is so the user do not need arrows when first option is the one they want.

I suspect an underlying keyboard manager is not being synced when calling `.goToFirst()'

### Reproduction

StackBlitz link: https://stackblitz.com/edit/go-to-first-issue-angular-aria-wpcbw3sz?file=src%2FApp.ts
Steps to reproduce:
1. Load stackblitz
2. Hit enter
Hitting enter should trigger en alert with the text "Option 0", but it does not happen

### Expected Behavior

When calling `.goToFirst()` the first option is selected and hitting Enter on the keyboard will select it.

### Actual Behavior

Nothing happens when hitting Enter

### Environment

- Angular: 21.1.3
- CDK/Material: 21.1.3
- Browser(s): Edge, Firefox
- Operating System (e.g. Windows, macOS, Ubuntu): Windows, Macos

Beginne mit der verlinkten StackBlitz-Reproduktion, insbesondere mit src/App.ts, und reproduziere die Sequenz .goToFirst() und anschließend Enter. Untersuche die vermutete Synchronisierung des keyboard-manager und überprüfe, dass das Drücken von Enter nach dem Wechsel zur ersten Option ein alert mit "Option 0" auslöst, ohne dass Arrow Down erforderlich ist.

Vom Indexierungsmodell aus dem Issue-Text verfasst.