Task/Issue URL:
https://app.asana.com/1/137249556945/project/1202552961248957/task/1216395465778162?focus=true
Tech Design URL (if applicable): 

### Description
Disable invalid tests

### Steps to test this PR

https://github.com/duckduckgo/Android/actions/runs/29049611345/job/86226720587
should pass

<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> **Low Risk**
> Test-only Maestro YAML changes; no app or production code is modified,
only reduced e2e coverage for specific AI-off configurations.
> 
> **Overview**
> Stops failing **unified input** Maestro flows from running in the
tagged `unifiedInputTest` nightly CI job.
> 
> `unified_input_open_duckai_back_to_ntp.yaml` no longer uses the
`unifiedInputTest` tag (`tags: []`), so the duck.ai icon / AI-off /
back-to-NTP matrix is kept in the repo but skipped when CI filters on
that tag.
> 
> In `unified_input_with_seeded_favorites.yaml`, the three **AI off**
(`inputWithAiToggle: "false"`) × omnibar scenarios are commented out
with a short note; the **AI on** seeded-favorites cases still run under
`unifiedInputTest`.
> 
> <sup>Reviewed by [Cursor Bugbot](https://cursor.com/bugbot) for commit
1e0c6a7efa63268db93871b3a7aa970658209497. Bugbot is set up for automated
code reviews on this repo. Configure
[here](https://www.cursor.com/dashboard/bugbot).</sup>
<!-- /CURSOR_SUMMARY -->

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>