Make notification IDs unique

Functional tests still need these on the page:
https://github.com/alphagov/notifications-functional-tests/blob/c9549ded6ab64ea61ba812a41cd7153541ceb784/tests/pages/pages.py#L917

tests/__init__.py

@@ -1,5 +1,6 @@
 import uuid
 from datetime import UTC, datetime, timedelta
+from itertools import repeat
 from unittest.mock import patch
 from urllib.parse import parse_qs, urlparse
 
@@ -552,10 +553,17 @@ def notification_json(  # noqa: C901
     if job:
         job_payload = {"id": job["id"], "original_file_name": job["original_file_name"]}
 
+    def _get_notification_id(index):
+        if index < 16:
+            return "{}{}{}{}{}{}{}{}-{}{}{}{}-{}{}{}{}-{}{}{}{}-{}{}{}{}{}{}{}{}{}{}{}{}".format(
+                *repeat(hex(index)[2:], 32)
+            )
+        return str(uuid.uuid4())
+
     data = {
         "notifications": [
             {
-                "id": sample_uuid(),
+                "id": _get_notification_id(i),
                 "to": to,
                 "template": template,
                 "job": job_payload,

tests/app/main/views/test_jobs.py

@@ -7,7 +7,7 @@
 from freezegun import freeze_time
 
 from app.main.views.jobs import get_time_left
-from tests import NotifyBeautifulSoup, job_json, notification_json, sample_uuid, user_json
+from tests import NotifyBeautifulSoup, job_json, notification_json, user_json
 from tests.conftest import (
     SERVICE_ONE_ID,
     create_active_caseworking_user,
@@ -117,7 +117,7 @@ def test_should_show_page_for_one_job(
     assert page.select_one("tbody tr a")["href"] == url_for(
         "main.view_notification",
         service_id=SERVICE_ONE_ID,
-        notification_id=sample_uuid(),
+        notification_id="00000000-0000-0000-0000-000000000000",
         from_job=fake_uuid,
     )