E2E Tests: Fix pre-onboarding maestro test (#7338)

Task/Issue URL:
https://app.asana.com/1/137249556945/project/1210594645151737/task/1212389758584564?focus=true

### Description
Fixes the pre-onboarding maestro test to account for an additional step

### Steps to test this PR
Run `maestro test
.maestro/onboarding/onboarding_dismiss_all_dialogs.yaml`

### UI changes
No UI changes

<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> Updates the pre-onboarding Maestro test to handle an additional AI
chat step in the onboarding flow.
> 
> - **E2E Tests**:
>   - Update `/.maestro/shared/pre_onboarding.yaml`:
> - Add `tapOn: "next"` and `assertVisible` for `".*want easy access to
private AI chat?.*"` to cover new onboarding step.
>     - Ensure flow continues to final `".*Try a search!.*"` screen.
> 
> <sup>Written by [Cursor
Bugbot](https://cursor.com/dashboard?tab=bugbot) for commit
f153631. This will update automatically
on new commits. Configure
[here](https://cursor.com/dashboard?tab=bugbot).</sup>
<!-- /CURSOR_SUMMARY -->

Author: landomen

.maestro/shared/pre_onboarding.yaml

@@ -12,7 +12,10 @@ appId: com.duckduckgo.mobile.android
 - tapOn: "choose your browser"
 - tapOn: "cancel"
 - assertVisible:
-      text: ".*where should I put your address bar?.*"
+    text: ".*where should I put your address bar?.*"
+- tapOn: "next"
+- assertVisible:
+    text: ".*want easy access to private AI chat?.*"
 - tapOn: "next"
 - assertVisible:
     text: ".*Try a search!.*"