FT: pin AppletMenuDismissTest to portrait viewport (800×1200)

Landscape layout activates sidebar CSS which causes #id_dash_content to
overlap the base-template h2 in CI headless Firefox, triggering
ElementClickInterceptedException. Portrait viewport sidesteps all
landscape breakpoints so the h2 sits safely above #id_dash_content.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/functional_tests/test_dashboard.py

@@ -119,6 +119,9 @@ class DashboardMaintenanceTest(FunctionalTest):
 class AppletMenuDismissTest(FunctionalTest):
     def setUp(self):
         super().setUp()
+        # Portrait viewport: sidebars don't activate, h2 sits safely above
+        # #id_dash_content and can't be obscured by it regardless of font metrics.
+        self.browser.set_window_size(800, 1200)
         Applet.objects.get_or_create(slug="username", defaults={"name": "Username"})
         Applet.objects.get_or_create(slug="palette", defaults={"name": "Palette"})
         self.create_pre_authenticated_session("discoman@example.com")