feat(telemetry): set App Insights authenticated user context for per-user tracing

[RodriSanchez1]

Closes #2206

What

Sets the Application Insights authenticated user context so that all telemetry (requests, dependencies, exceptions, customEvents, traces, pageViews) carries a user_AuthenticatedId, making per-user tracing trivial:

union requests, dependencies, exceptions, customEvents, traces
| where timestamp > ago(90d)
| where user_AuthenticatedId == "<USER_ID>"
| order by timestamp asc

Previously the only user identifier was on the Firebase side, so finding a user's telemetry in App Insights meant fragile string-matching of the id/email inside dependency URLs — and events/exceptions/traces/page views couldn't be tied to a user at all.

Changes

• Login.actions.js
  • loginSuccess: appInsights.setAuthenticatedUserContext(payload.id) on login success (alongside the existing FirebasePlugin.setUserId).
  • logout: appInsights.clearAuthenticatedUserContext(). This also covers the People logout path, which dispatches the same logout() action.
• App.container.js: re-apply setAuthenticatedUserContext(userId) on app start for already-logged-in users, since the context is per-session and must be re-applied on each launch. Placed in its own block (not inside the Cordova-only analytics init) because the context applies to web telemetry too.
• All calls are wrapped in try/catch to mirror the existing defensive Firebase/gtag handling.
• Tests added for the login (set) and logout (clear) behavior.

Important: identifier choice

Uses the Mongo user _id (the same value already passed to FirebasePlugin.setUserId), never the email. The email is PII and would be persisted in Azure; the opaque _id is the correct identifier.

Compatibility

@microsoft/applicationinsights-web@2.8.18 (the pinned version) exposes both setAuthenticatedUserContext and clearAuthenticatedUserContext on the main ApplicationInsights class — verified against the package typings.

Acceptance criteria

• user_AuthenticatedId is populated on telemetry for logged-in users (requests, dependencies, exceptions, custom events, traces, page views).
• The identifier used is the Mongo _id, not the email.
• Context is set on login and re-applied on app start for already-logged-in users.
• Context is cleared on logout.

Testing

yarn test --watchAll=false --testPathPattern="Login.actions" → 15 passed (incl. 2 new tests).

Follow-up (out of scope)

The UserData_EmailLost instrumentation noted in the issue is tracked separately.

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