CI: added installation of the Notes app (#187)

During this PR(#184) we had
found that in some cases we can broke the AppAPI Auth.

This PR adds check for this, as CORS bypassing is used for the Notes app
to work and it is achieved by setting 'app_api' session key.

.github/workflows/tests.yml

@@ -74,6 +74,14 @@ jobs:
         with:
           path: apps/${{ env.APP_NAME }}
 
+      - name: Checkout Notes
+        uses: actions/checkout@v4
+        if: ${{ !startsWith(matrix.server-version, 'master') }}
+        with:
+          repository: nextcloud/notes
+          ref: "main"
+          path: apps/notes
+
       - name: Set up php ${{ matrix.php-version }}
         uses: shivammathur/setup-php@4bd44f22a98a19e0950cbad5f31095157cc9621b # v2
         with:
@@ -106,6 +114,10 @@ jobs:
           ./occ app:enable notifications
           ./occ app:enable --force ${{ env.APP_NAME }}
 
+      - name: Enable Notes
+        if: ${{ !startsWith(matrix.server-version, 'master') }}
+        run: ./occ app:enable notes
+
       - name: Run Nextcloud
         run: PHP_CLI_SERVER_WORKERS=2 php -S 127.0.0.1:8080 &