docs: name the Configuration tab as it is rendered, drop an unused fixture

Round 6's two remaining nits. The operator note said "Configuration → Email"
but the group renders as "Email / SMTP" in both locales, and
test_an_admin_can_activate_a_pre_approved_registrant requested make_user without
using it — a leftover from the reverted rounds that made the test look like it
seeded an admin when it did not.

backend/tests/test_auth_session.py

@@ -209,7 +209,7 @@ def test_registration_with_an_already_pending_request_persists_the_account(
     assert notified == ["pia@example.com"]
 
 
-def test_an_admin_can_activate_a_pre_approved_registrant(db, make_user, monkeypatch):
+def test_an_admin_can_activate_a_pre_approved_registrant(db, monkeypatch):
     # The recovery path for the account above, pinned so it cannot quietly break: re-entering the
     # address in the Access-requests whitelist box (POST /api/admin/invites) runs
     # _activate_user_by_email, which is also what keeps the SEC-10 preset-password guard in play.

frontend/src/lib/releaseNotes.ts

@@ -22,7 +22,7 @@ export const RELEASE_NOTES: ReleaseEntry[] = [
     fixes: [
       "Such a sign-up now creates the account. Before, there was nothing behind the request for an admin to approve, and every retry silently repeated the same nothing. Other sign-ups were unaffected — a brand-new address, one that had been denied and was asking again, and every sign-up on an instance with working email all created their account as expected.",
       "Admins: a new account still starts inactive. If the person had merely requested access, approve their request as usual. If you had already whitelisted their address, there is no pending request to approve — re-enter the address in the whitelist box under Users → Access requests and that activates their account.",
-      "Operator note: an incomplete SMTP setting makes Siftlode skip every message silently by design — that is what left the sign-ups above with nothing to fall back on. If your instance has never delivered mail, check Configuration → Email and use “Send test email”.",
+      "Operator note: an incomplete SMTP setting makes Siftlode skip every message silently by design — that is what left the sign-ups above with nothing to fall back on. If your instance has never delivered mail, check Configuration → Email / SMTP and use “Send test email”.",
     ],
     chores: [
       "Registration commits the new account explicitly. upsert_pending_invite() commits only when it actually writes an invite row — not when the address already has a pending or approved one — and the only other commit on that path is gated on working SMTP, so with mail unavailable the flushed user row was rolled back when the background task's session closed. That one line is the whole behavioural change in production; the only other shipped edit is a test-only RateLimiter.reset() helper. Two attempts to also fix the pre-approved account's activation UX were reverted after review — roadmap UX-25 records both dead ends and the safe shape.",