test: add metametrics to collect qa stats (#27696)

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## **Description**

This updates
[.github/scripts/collect-qa-stats.mjs](vscode-file://vscode-app/Applications/Cursor.app/Contents/Resources/app/out/vs/code/electron-sandbox/workbench/.github/scripts/collect-qa-stats.mjs)
so QA stats include E2E MetaMetrics coverage in its own top-level
metametrics namespace (alongside unit, component_view, e2e, and
performance).

The script statically scans event display names that tests assert: it
walks tests/helpers/analytics/expectations/*.ts and an explicit
LEGACY_INLINE_METAMETRICS_PATHS list for specs/helpers that still use
inline checks (getEventsPayloads, event.event ===, etc.). It resolves
onboardingEvents.* using tests/helpers/analytics/helpers.ts. Emitted
keys are metametrics_events_checked_unique_count and
metametrics_events_checked_names_json (sorted JSON array of names).

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## **Changelog**

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CHANGELOG entry:

## **Related issues**

Fixes:

## **Manual testing steps**

```gherkin
Feature: my feature name

  Scenario: user [verb for user action]
    Given [describe expected initial app state]

    When user [verb for user action]
    Then [describe expected outcome]
```

## **Screenshots/Recordings**

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### **Before**

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### **After**

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## **Pre-merge author checklist**

- [ ] I've followed [MetaMask Contributor
Docs](https://github.com/MetaMask/contributor-docs) and [MetaMask Mobile
Coding
Standards](https://github.com/MetaMask/metamask-mobile/blob/main/.github/guidelines/CODING_GUIDELINES.md).
- [ ] I've completed the PR template to the best of my ability
- [ ] I've included tests if applicable
- [ ] I've documented my code using [JSDoc](https://jsdoc.app/) format
if applicable
- [ ] I've applied the right labels on the PR (see [labeling
guidelines](https://github.com/MetaMask/metamask-mobile/blob/main/.github/guidelines/LABELING_GUIDELINES.md)).
Not required for external contributors.

## **Pre-merge reviewer checklist**

- [ ] I've manually tested the PR (e.g. pull and build branch, run the
app, test code being changed).
- [ ] I confirm that this PR addresses all acceptance criteria described
in the ticket it closes and includes the necessary testing evidence such
as recordings and or screenshots.


<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> **Medium Risk**
> Changes the QA metrics pipeline by adding a new `metametrics`
namespace and altering artifact sourcing (optional fixture mode), which
could affect downstream dashboards/alerts if parsing or artifact naming
assumptions break.
> 
> **Overview**
> Extends `.github/scripts/collect-qa-stats.mjs` to emit a new top-level
`metametrics` namespace in `qa-stats.json`, populated by a static scan
of E2E sources to count and list unique MetaMetrics event names asserted
in tests.
> 
> Adds an optional local fixture mode (`QA_STATS_FIXTURE_ROOT`) that
bypasses the GitHub API/token and reads artifacts from extracted
directories, and tweaks E2E logging/output to better handle runs without
JUnit artifacts and to print the JSON body after writing.
> 
> <sup>Written by [Cursor
Bugbot](https://cursor.com/dashboard?tab=bugbot) for commit
b371f3602bac194f6b4f55a3355bea7a9c1a6f01. This will update automatically
on new commits. Configure
[here](https://cursor.com/dashboard?tab=bugbot).</sup>
<!-- /CURSOR_SUMMARY -->

Author: racitores